Originally Posted by
mattack4000
... Is this something I can change at check in or at Istanbul or does it have to be done now (I don't see option to take that later flight or any flight) since it is an AC award ticket?
Changes to AC award ticket will have to be done by AC [So a question for the AC forum]
How many hours between landing and the time you would prefer to leave the next day? Is there award availability on that flight?
It may (or may not) change it from a (airside) transit to a stopover with immigration/emigration taxes/fees.