When using "Transfer Help Desk Request" action, what is the purpose of "A specific person" option?

Summary:

When using the "Transfer Help Desk Request" action, there are three options in the field Transfer this Service Request to field. There are three options. I've observed and understand behavior of two of them, but not the third.

1. Another member of the current queue: we pick the transfer reason, a transfer note and Assigned To
2. Another set of resources: in addition to the above fields, the Queue field is displayed and we can select another queue and then members of that queue in the Assigned To field

1. A Specific Person: Only the Transfer Reason, Transfer Note, and Assigned To