If your booking is made within 10 weeks of departure then full payment must be made. (friendshiptravel.com)
You might also pay a «close - in» fee for booking award flights within a few weeks of departure. (nerdwallet.com)
Aeroplan changed my 2 F seats to J on Swiss automatically, do you think I could still plead my case and get it changed to Lufthansa within 2 weeks of departure if the availability is there? (milenomics.com)