You'd go to the membership portal (Google six flags membership portal). You're unable to do it before the 12 months have passed though. As long as that time frame has passed you shouldn't have any issues.
I would contact the customer service representative
I dont think they are Refundable
Memberships usually come with a 12month agreement...if you're beyond the 12months...try the portal...if that doesn't work call customer service... because your credit card is on file....
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