If you want to remove/re-send a pending collaboration invitation, go to the folder/file and look at the Collaborators panel on the right. Here you will see a list of all confirmed and pending collaborators.
Click Pending below the collaborator's email address.
This will bring up a menu with options to Resend Invite or Remove the collaborator.
If a collaborator has already auto-accepted an invitation and you would like to revoke their access, follow these steps:
1. Click on the current access level under the user's name you want to remove.
2. Select the Remove option on the dropdown menu.