In a few weeks, I will be finishing a trip and flying into EWR (arriving 6:42pm) and then leaving for a trip to PBI at 9:05pm. Since these 2 trips were planned at separate times, they are currently on 2 separate reservations. Is it possible to merge these 2 reservations so if my flight arriving into EWR is late and I miss the flight to PBI I will be re-accommodated on a PBI flight the next morning?

I just called the Elite Desk and the (some what short) rep told me it was not possible to merge 2 records and I would be charged to fly the next morning if I missed my PBI flight. Is this true? Somewhat surprising...

Any advice?