Originally Posted by somedude3210

You can call Amex and ask them to take off the associated Aeroplan number for the online transfer. You might have to give them some sort of excuse but no real hassle for them to do it.

After the call sign into your Amex account online and you'll be able to add another aeroplan number. I believe it'll validate the aeroplan account as long as the last name and address match.