Why can't I change the email address of my login or a crew member's login?

When a user is linked to a global profile, you can not change the email address of this user's login from within the workspace. 

To change the email address, the crew member should: 

1. Click on the crew member name in the upper-right corner.
2. Click "Return to workspaces".
3. Navigate to your username in the right corner. 
4. Choose Settings.
5. Change your email address under 'Language'.