Only a 'Team Leader' (the person who created the team or was assigned the leader by the admin) can cancel pending invites.

Visit the "My Team" page.

On the pending invite row, click on the 'Cancel Invite' button.

You will be asked to confirm if you want to cancel the invite - click "OK" to cancel.

Go to your 'My Team' page

Scroll down the page until you see the pending invite and click on the 'X' on the right hand side.

You will be asked to confirm you want to delete the pending invite.