diff --git a/src/bot.ts b/src/bot.ts
index 4a5ef8a..b65e462 100644
--- a/src/bot.ts
+++ b/src/bot.ts
@@ -13,6 +13,7 @@ import {
 	SlashCommandRoleOption,
 	SlashCommandStringOption,
 	SlashCommandSubcommandBuilder,
+	SlashCommandUserOption,
 } from "npm:discord.js@14.14.1";
 import { RuleSet } from "./rules.ts";
 import { channel, log_from, SimpleResult, split_promise, try_ } from "./utils.ts";
@@ -35,9 +36,7 @@ export class EpitlsBot {
 		this.bot.on("interactionCreate", (interaction) => this.handle_interaction(interaction));
 		this.rest = new REST().setToken(bot_token);
 		this.rules = rules;
-		this.assoc_channel = channel<
-			{ cri_login: string; discord_user_id: string; callback: (success: SimpleResult) => void }
-		>();
+		this.assoc_channel = channel<Association | Dissociation>();
 	}
 
 	/**
@@ -116,7 +115,7 @@ export class EpitlsBot {
 	private async register_commands() {
 		const assoc_cmd = new SlashCommandBuilder()
 			.setName("associate")
-			.setDescription("Associates a cri account to your discord account.")
+			.setDescription("Associes un utilisateur cri avec votre compte discord.")
 			.addStringOption(
 				new SlashCommandStringOption()
 					.setName("cri_email")
@@ -124,10 +123,21 @@ export class EpitlsBot {
 					.setRequired(true),
 			).toJSON();
 
+		const ADMIN_PERMISSIONS = 0x0000000000000008n;
+		const dissoc_cmd = new SlashCommandBuilder()
+			.setName("dissociate")
+			.setDescription("Dissocies un utilisateur cri de votre compte discord.")
+			.setDefaultMemberPermissions(ADMIN_PERMISSIONS)
+			.addUserOption(
+				new SlashCommandUserOption()
+					.setName("user")
+					.setRequired(true),
+			).toJSON();
+
 		const rule_cmd = new SlashCommandBuilder()
 			.setName("rule")
 			.setDescription("Gestion des règles d'associations groupes cri / rôles.")
-			.setDefaultMemberPermissions(0x0000000000000008n)
+			.setDefaultMemberPermissions(ADMIN_PERMISSIONS)
 			.addSubcommand(
 				new SlashCommandSubcommandBuilder()
 					.setName("list")
@@ -172,7 +182,7 @@ export class EpitlsBot {
 		for (const guild_id of this.bot.guilds.cache.keys()) {
 			await this.rest.put(
 				Routes.applicationGuildCommands(this.bot.application!.id, guild_id),
-				{ body: [assoc_cmd, rule_cmd] },
+				{ body: [assoc_cmd, dissoc_cmd, rule_cmd] },
 			);
 		}
 	}
@@ -180,6 +190,7 @@ export class EpitlsBot {
 	private async handle_interaction(interaction: Interaction<CacheType>) {
 		if (!interaction.isChatInputCommand()) return;
 		if (interaction.commandName === "associate") await this.handle_command_associate(interaction);
+		if (interaction.commandName === "dissociate") await this.handle_command_dissociate(interaction);
 		if (interaction.commandName === "rule") {
 			const subcommand = interaction.options.getSubcommand();
 			if (subcommand === "list") await this.handle_command_rule_list(interaction);
@@ -198,7 +209,7 @@ export class EpitlsBot {
 		const discord_user_id = interaction.user.id;
 		const { promise, resolver } = split_promise<SimpleResult>();
 
-		this.assoc_channel.send({ cri_login, discord_user_id, callback: resolver });
+		this.assoc_channel.send({ kind: "associate", cri_login, discord_user_id, callback: resolver });
 		await interaction.reply(message_command_response_assoc_pending(email));
 		log(`Started verification for discord id '${discord_user_id}' with cri login '${cri_login}'.`);
 		const result = await promise;
@@ -206,6 +217,16 @@ export class EpitlsBot {
 		else interaction.editReply(message_command_response_assoc_error(result));
 	}
 
+	private async handle_command_dissociate(interaction: ChatInputCommandInteraction<CacheType>) {
+		const user = interaction.options.getUser("user");
+		if (user === null) throw new Error("Unreachable.");
+		const discord_user_id = user.id;
+		const { promise, resolver } = split_promise<SimpleResult>();
+		this.assoc_channel.send({ kind: "dissociate", discord_user_id, callback: resolver });
+		await promise;
+		await interaction.reply(message_command_response_dissoc_success());
+	}
+
 	private async handle_command_rule_list(interaction: ChatInputCommandInteraction<CacheType>) {
 		const guild_id = interaction.guildId;
 		if (guild_id === null) {
@@ -261,6 +282,19 @@ export class EpitlsBot {
 	}
 }
 
+export type Association = {
+	kind: "associate";
+	cri_login: string;
+	discord_user_id: string;
+	callback: (success: SimpleResult) => void;
+};
+
+export type Dissociation = {
+	kind: "dissociate";
+	discord_user_id: string;
+	callback: (success: SimpleResult) => void;
+};
+
 function message_command_response_assoc_pending(email: string) {
 	const embed = new EmbedBuilder()
 		.setTitle("`🟡`| Association")
@@ -328,6 +362,13 @@ function to_comparable(input: string) {
 		.replace(/\p{Diacritic}/gu, ""); // remotes accents
 }
 
+function message_command_response_dissoc_success() {
+	const embed = new EmbedBuilder()
+		.setTitle("`✅`| Dissociation")
+		.setDescription("Votre compte Discord a bien été dissocié de votre compte CRI.");
+	return { embeds: [embed] };
+}
+
 function display_rule(rule: GuildRule) {
 	if (rule.include_historical) return `- \`${rule.group_id}\` [H] → \`@${rule.role_name}\``;
 	else return `- \`${rule.group_id}\` → \`@${rule.role_name}\``;
diff --git a/src/main.ts b/src/main.ts
index c6ffc86..58ee3e1 100755
--- a/src/main.ts
+++ b/src/main.ts
@@ -61,8 +61,9 @@ class Service {
 
 		// for all received associations, trigger the association procedure.
 		(async () => {
-			for await (const { discord_user_id, cri_login, callback } of this.bot.receive_associations()) {
-				this.association_procedure(discord_user_id, cri_login).then(callback);
+			for await (const req of this.bot.receive_associations()) {
+				if (req.kind === "associate") this.association_procedure(req.discord_user_id, req.cri_login).then(req.callback);
+				if (req.kind === "dissociate") this.dissociation_procedure(req.discord_user_id).then(req.callback);
 			}
 		})();
 
@@ -121,6 +122,11 @@ class Service {
 		}
 		return true;
 	}
+
+	async dissociation_procedure(discord_user_id: string): Promise<SimpleResult> {
+		await this.state.remove_user(discord_user_id);
+		return true;
+	}
 }
 
 // bot.assign_role_to_member("358338548174159873", "871777993922588712", "1202346358867238952");
diff --git a/src/state.ts b/src/state.ts
index 3459188..938eac2 100644
--- a/src/state.ts
+++ b/src/state.ts
@@ -1,6 +1,6 @@
 import { v1 as uuid } from "https://deno.land/std@0.213.0/uuid/mod.ts";
 
-export type StoredUser = { discord_user_id: string; cri_login: string };
+export type StoredUser = { discord_user_id: string; cri_login: string; uuid: string };
 /**
  * Wraps the persistent state, containing user associaitons.
  */
@@ -44,32 +44,46 @@ export class State {
 	/**
 	 * Get the association of a user given its discord user id.
 	 */
-	public async get_user(discord_user_id: string) {
+	public async get_user_by_discord_id(discord_user_id: string) {
 		const { value: user_uuid } = await this.kv.get(["users_by_discord_id/", discord_user_id]);
 		if (user_uuid === null) return undefined;
 		const { value: stored } = await this.kv.get(["users/", user_uuid as string]);
 		return stored as StoredUser;
 	}
 
+	/**
+	 * Get the association of a user given its cri login.
+	 */
+	public async get_user_by_cri_login(cri_login: string) {
+		const { value: user_uuid } = await this.kv.get(["users_by_cri_login/", cri_login]);
+		if (user_uuid === null) return undefined;
+		const { value: stored } = await this.kv.get(["users/", user_uuid as string]);
+		return stored as StoredUser;
+	}
+
 	/**
 	 * Appends a new user association.
 	 */
 	public async set_user(discord_user_id: string, cri_login: string) {
+		const old_discord = await this.get_user_by_cri_login(cri_login);
+		if (old_discord !== undefined) await this.remove_user(old_discord.discord_user_id);
 		await this.remove_user(discord_user_id);
 		await this.add_user(discord_user_id, cri_login);
 	}
 
 	private async add_user(discord_user_id: string, cri_login: string) {
 		const user_uuid = uuid.generate() as string;
-		const stored: StoredUser = { discord_user_id, cri_login };
+		const stored: StoredUser = { discord_user_id, cri_login, uuid: user_uuid };
 		await this.kv.set(["users/", user_uuid], stored);
 		await this.kv.set(["users_by_discord_id/", discord_user_id], user_uuid);
+		await this.kv.set(["users_by_cri_login/", cri_login], user_uuid);
 	}
 
-	private async remove_user(discord_user_id: string) {
-		const { value: user_uuid } = await this.kv.get(["users_by_discord_id/", discord_user_id]);
-		if (user_uuid === null) return undefined;
-		await this.kv.delete(["users/", user_uuid as string]);
+	public async remove_user(discord_user_id: string) {
+		const user = await this.get_user_by_discord_id(discord_user_id);
+		if (user === undefined) return;
+		await this.kv.delete(["users/", user.uuid]);
 		await this.kv.delete(["users_by_discord_id/", discord_user_id]);
+		await this.kv.delete(["users_by_cri_login/", user.cri_login]);
 	}
 }