BEWARE!!

The system did not let me use the second credit tied to the same PNR. It said the credit has expired. So make sure the 60+ day flight is slightly cheaper than the original.

When I first called in, the rep said I can only use this ghost credit over the phone, but they would waive the agent booking fee. I later initiated a chat session to book the new flight, and a very helpful agent was able to fix the ghost credit.