To remove a collaborator from your board:

1. Sign in to your account and navigate to the Projects page. 
2. Click the Boards tab. Click to open the desired board.
3. Beneath the board title, click the + icon (). 
4. To remove a collaborator, click the checkmark next to a their name.
   
5. At the bottom of the pop-up modal, click Update. 

The collaborator should be successfully removed form the board.