In case the invitation that you have sent expired before the user accepts it or in cases that invitation didn't come, then you have the option to resent it without filling the invitation form again.
Note: Keep in mind that if you will reinvite user multiple times, then only the last activation link will be active, and also it will expire 24 hours after you resent the last invitation.
Step by step
1 Log into MyServices at myservices.revolgy.com
2 Click the "Users" tab in the navigation
3 Click the "Invite Again" button next to "Invitation expired" status
4 User will automatically receive an email with a new activation link, which will be active for the next 24 hours. If the user will not accept the invitation, then it will expire again and you will have to repeat this process again.