Within Teamwork Desk you can resend invites Desk invites to users who have not yet accepted.
Note: Any invite you send will expire after 24 hours.
To resend the invite click on your profile icon to the top right of the navigation bar and select Settings.
In the settings area, select the Users tab.
You will then see a list of users. Select the one you wish to re-invite.
On the left pane select Profile.
Scroll to the bottom of the profile to see an option to re-invite.
For more information see: Adding users