Currently, there is not an available feature to move waitlisted people to be regular registrants within a Registration form. Blackbaud has an idea bank that our clients can go to list any suggestions they have for our programs. You  enter suggestions and vote for your favorite suggestions as well. This is a direct line to our programming team and they look at this for enhancements to the software.


Workaround:
Step1: Run a report to view the waitlisted people
  1. Communities > Forms > Registration
  2. Hover over the form's name, click Reports
  3. Report type would be People:Additional Contacts & Waitlist
  4. Select People: Waitlist
  5. Click Run Report
  6. Click Next
  7. Mark the fields: supporter_id and other necessary fields
  8. Click Finish
  9. Choose No, run report immediately
  10. Click Run Report
  11. Click Export CSV link and save the spreadsheet on your computer

Step 2: Add the waitlisted people as registrants (this can be done manually one-by-one or you can do via batch entry)
-How to import a batch of registrations for a form

OR

-How to enter an offline registration in a Registration Form