You can remove a team member invitation by navigating into the account settings.
Click on your current account name in the top left corner of your dashboard (V2) and click on the “Account Settings” button.
You can get to the same page by clicking on the “Settings” button in the main menu on the left.
Under the account details and settings you can see the “Pending team invitations” section which will display all users that are invited to your team and not yet accepted the invitation.
Simply click on the “Delete” (Trash) icon on the right. You will be prompted to confirm your action and if you do, the invitation will be removed.