Try other airports using one-way segment searches. For example, try looking for IAH-IST to get across the Atlantic? I see J for late Sep. But then from IST you'd need to connect through RUH and then into DEL, but still in J.

Concur with exc. No change fee involved if you book a J reward, with some Y segments and then find J segments on the exact same flight opening up later on. But you do need to call in to get moved up from Y to J on that flight (for free).

Otherwise, it's now $100 change fee per direction for other changes to an Aeroplan itinerary.
http:/www.aeroplan.com/faqhelp/5314?currentLanguage=en