Need to change spouse's SIN but I've already filed my return.

I accidentally entered my spouse's old SIN then completed both of our taxes. I filed mine but was having trouble filing his. Once I realized it was due to the incorrect SIN I tried to change it but I believe the fact that mine is already filed means that I cannot make any changes. 

Will I have to wait for my assessment then do a refile? Or is there a way to update the info and resend my return?