you are supposed to get a residual FFC, which is a cross between the traditional FFC AND ETC. to use it, you’d use the PNR it came from using the ‘future flight credit’ form of payment when paying. Key things are the credit has to be used for the same passenger, but can be used on partners if desired, and will be valid from a year of the change.

if the system is not showing the credit on the step before you confirm, don’t complete online. I forget the steps it shows, but if it ain’t showing the credit, call to have this done. You’ll also get an email with the credit once the cancel is completed.

on that note, having done a same flight price drop not too long ago, it is NOT seamless, even though there are no change fees. In order to be able to ‘change’ to the same flights, you need to first change to a different flight (Id do one that costs the same as original, or one at the new price), then change back. I tried as a cancel and then rebook online - while it issued the credit as an [traditional] FFC, it would not let me select the same flights, even when it showed just the fare and no flights attached to the record. The only way I could do it online is to change to different flights, then change back.

you can try and call, but YMMV on how agents might handle. While some will likely process it, ive had someone tell me you can’t get a price drop on the same flight, and that you could only do it for $50 fee within a month of booking. If you get an agent saying this, HUCA, I guess. I’d try online using the two-step method if possible. If the computer will do it correctly, just let it do it.