You can simply cancel the flight. No need to rebook now; you only pay the change fee when you rebook your flight. You have up to 1 year from the date you originally made the reservation (i.e. the date you bought the ticket, not the date you were scheduled to start travel) to start travel on a revised booking. If you don't rebook, you simply forfeit your points without incurring a change fee.
It's up to you to decide whether the change fee is worth it or not. $400 for 62,000 points is 0.64 CPM. If you can get more value out of the points than that, then its worth it, IMHO, but there are also various opinions on comparing to revenue tickets due to differing conditions such as limited availability of seats, higher restrictions on award tickets, etc.
Also, if you want to get your points back, you'd need to rebook for a flight over 22 days out, and then pay a change fee to cancel. This will incur 2 fees, so IMHO wouldn't be worth it.
https://www.aeroplan.com/faqhelp/531...entLanguage=en
There is no fee at time of cancellation, but the change fee (as per above chart) will apply when you re-book your trip.