My family and I are using some AP points this summer for a trip; things have changed on the return, and we can't change return flights. (I'm a lowly scum-of-the-earth E)(We bought CanJet to return, refusing to give the cash to AC.)

I was going to throw the return away, but am now thinking, for $25 per ticket, I can pick some date in the future, and who knows, maybe use them as the return (for flights I would purchase on Jetsgo or Canjet just out of spite.)

Question -- how far out can I set the date for the return? And is there an absolute outer limit in terms of the date?