You must be a Team Admin or Owner to remove someone from a Slack channel. Open the Slack app on your computer (or click “Log In” at Slack.com to begin.If the channel is public, the person you remove will still be able to view the channel history and archived files. They can also rejoin the channel if they wish.
If the channel is private, the person will not be able to view files or the channel history unless they are added back to the channel.;
, If you’re not already logged in to your team, enter your team name and user credentials when prompted. You will arrive at your team’s default channel, usually #general.Note that you can’t remove a team member from #general (or other default team channels).
 Click the name of the channel (e.g., “#channel”) on the left column to join.
 This icon (which looks like a 2-pane window) is near the top of the screen, directly to the left of the Search box. A menu called “About ” will expand on the right.
 Now you’ll see a list of everyone who’s a part of the channel.
 A small menu will appear.
 Now you’ll see a confirmation screen appear.
 Slackbot will send a message to this team member to inform them that they’ve been removed.
Open Slack.
Sign in to your team.
Join the channel.
Click the “Show Channel Details” icon.
Click “Members” in the “About #” menu.
Click the user you want to remove.
Click the “Remove from #” link.
Click “Yes, remove them” to save your changes.
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