The odds of someone having four PDX-FLL award tickets confirmed for the day and flight you need it strike me about the same as the chances of winning the Megabucks. And even if such a person exists, I don't know that WN would permit the swap.

I think you have a better chance of award availability opening up between PDX-FLL; numerous participants here have reported award availability becoming available close in -- although getting four seats might be a stretch. I have personally experienced my preferred flight becoming available a day or two before -- or even the day of -- my scheduled travel, but in such cases I was only looking for one or, at the most, two seats.

You should be checking for availability two or three times daily using the change flight feature in Travel Tools.

Good luck.