Receive a Check-in object from the check-in page containing relevant user information.

- The Backend should be able to receive a check-in information that stores the Last Name, SSN(only for verification NOT STORING), the transportation type , job assignment, phone number (optional)

Start at the check-in page and locate the backend entry point that receives check-in information. Verify how last name, transportation type, job assignment, and optional phone number are handled, and ensure SSN is used only for verification and not stored; done means the backend accepts the required check-in data without retaining SSN.

Written by the indexing model from the issue text.