Yes! If you are an admin, you have the ability to cancel invites. Simply:
- Click the drop down arrow at the top of your left hand navigation menu
- Select "admin" in the dropdown
- Select "invitations" on the navigation bar
- Then click the trash icon next email address you wish to un-invite
Note* If that user already accepted the invite and created a profile, you will have to remove them from the organization. To learn how to remove a user, check out this FAQ.