When you assign a user or group to an extranet space, you must specify user(s) roles. The permissions set by the administrator are linked to this role.

Define permissions and the names of the roles

You can modify the permissions for each role as you require and change the name of the roles.

When you check the boxes for a role, users assigned to that role have those permissions.
Uncheck the boxes to remove permissions from the role.

When you change the permissions of a role, the permissions of all users already assigned to that role will be updated accordingly.