JAVASCRIPT

remove a user from a reaction discord.js

<Message>.reactions.resolve(EMOJI).users.remove(USER)
<MessageReaction>.users.remove(USER)

discord.js remove reaction

Since this question is getting a lot of attraction, I decided to post what worked for me

Remove Specific User's Specific Reaction

// Channel = the channel object of the message's original channel
// MessageID = ID of the message, if hard coding, put around quotations eg: "1234"

const msg = await channel.messages.fetch(MessageID);

msg.reactions.resolve("REACTION EMOJI, 
REACTION OBJECT OR REACTION ID").users.remove("ID OR OBJECT OF USER TO REMOVE");
Note: If using an older version of discord.js, simply replace channel.messages.fetch with channel.fetchMessage

discord js remove reaction from user

const userReactions = message.reactions.cache.filter(reaction => reaction.users.cache.has(userId));

try {
	for (const reaction of userReactions.values()) {
		await reaction.users.remove(userId);
	}
} catch (error) {
	console.error('Failed to remove reactions.');
}