There are three ways to remove users from within Synapse:
Remove Admins from an Account
If you would like to remove an Admin from your account, please contact: firstname.lastname@example.org.
Remove Users/Design Owners from an Account
As an Admin, you can remove users/Design Owners from your account if they have not yet accepted the invitation.
Visit the Users section on the dashboard.
Click the three dots to the right of the user's name.
If a user has already accepted their invitation, please contact email@example.com to have the user removed.
Remove Collaborators from a Design
As a Design Owner, or as an Admin, you can remove Collaborators from a specific design.
Visit the design you'd like to remove the Collaborator from.
Click the collaboration icon.
Click the three dots to the right of the Collaborator's name.