Projects change and team members move on from time-to-time. Permanently remove them from your account in the Account Information section.
Remove members:
1. Click your user name/avatar at the top right of the page.
2. Click Account Info.
3. Hover the cursor over the appropriate member.
4. At the far right of the permissions for the member, select Options to display the drop-down.
5. Click Remove user.
6. Click Accept to permanently* delete the user from your account and all associated events.
*If uncertain whether they will work with you again (perhaps they are a freelancer), remove all permissions as a less permanent option.