Just tried contacting AM via their Chat function to extend my 65,000 miles expiring June 2022.
Sadly AM was not helpful. They pointed me to their Offers page where a current miles extension promo is running, but none of those options are viable for me.

Thought my status as GO would help push the case for a +1 yr extension... Agent simply said no, it can't be done. Disappointed.

Will try calling and speaking with human next time....