You can edit a collaborator’s permissions at any time. Only the project owner can edit collaborators’ permissions.
From the list of groups and collaborators, click on the name of the collaborator you want to edit
Open the "Permissions" tab, and make the changes you want in the permission settings (see “Set permissions”)
Click "Update"
A collaborator can be part of several groups simultaneously. The group-level access defined in the permissions tab will then be valid for all groups the collaborator is part of. See how to remove or add collaborators to a group in “View, edit, and delete project groups”. A collaborator can also be part of no group, but still be part of the project. For an overview of your groups and collaborators
Go to the "Collaboration" window
Choose "Groups" on the left side of the screen to view all groups
Choose "Collaborators" on the left side of the screen to view all collaborators