1. Swapping: If it is entirely empty and you don’t mind getting a different tank, go for it, BUT look on the collar to make sure it is NOT expired since if you change your mind and want to do #2 later, you’d need to get it recertified or come back here to #1. Look at the collar for a MM-YY date, if it is < 10 yrs old, then you are good. If it is NOT EMPTY, then you forfeit any propane left in it.
2. Refill: If not empty, you don’t lose any of the propane that was in it. Make SURE you find out from the “refilling” station is you will be charged by how much dispensed or flat rate. If it is flat rate and you have any propane left, you are being ripped and charged for propane already left in the tank.
Just some food for thought on propane 🙂