These steps explain how to change the type of access a guest already has, or remove it altogether. If you want to know how to invite a guest to begin with, see here:📄 Invite someone as a guest to a specific file
Guests can either be invited as an Editor or Commenter:
Editor: Can edit and share this specific file
Commenter: Can view and comment on this specific file
As a full workspace member, you can change the type of access a guest has by opening the editing page of the file they have access to, clicking on Invite in the top right corner, and changing their access in the dropdown.
Only teamspace directors can remove a guest's access. They can't remove a guest's access to a specific file, but they can remove the guest from a teamspace or workspace via the teamspace or workspace settings.