It is a waste of time.

You are trying to do what thousands of people do every day. After speaking with a supervisor, the record of what you were told was likely entered in your PNR notes. This means that no matter how many times you call, you will be told the same thing.

If the reason for the change that brings you to Baltimore now would be covered by your travel insurance, consider putting in a claim for the difference. If the reason is work-related, most employers will cover the cost of the changes.

Simply put, when you change a WN reservation, your ticket is refared. You pay the new fare for the route you wish to travel. If the cheaper fares are gone because others have bought them, you will pay the fare difference to the best fare available.

And, as you have been told, if you noshow for your ticket origination at PVD, your entire ticket will be cancelled. Depending on the fare basis booked, there may or may not be value left with which to purchase a new ticket.

Doesn't help OP, but a good lesson for those who think that because WN advertises "no change fees" that it does not cost a ton of money to change a ticket. It may or it may not.

OP's best bet here is to find the cheapest one-way from BWI to PVD and start his original ticket or to purchase the new ticket and eat the fare difference. Have no idea what he booked and what he is now quoted, but it is possible that the best fare available will be a higher fare if he waits.