In order to cancel a pending Private Group invite, or delete any other invitation from the list of users in your Private Group from an iPhone with Glympse version 3.20 and above:
1. From the Private Group map, navigate to Private Group where you will see a list of invites (expired) and pending invites will appear. Slide left over the invite you would like to remove.
4. Tap on the Remove button.
5. The Invites list will be updated and remove the user's invite from the list.
6. The user will no longer be able to access the Private Group.