Every Studio pass is a one-time payment for 7 or 30 days. Studio never charges you again automatically.
There is nothing to cancel
When the pass ends, your account moves to Free. If you do not want another pass, simply do not buy one.
Want to keep going?
Before or after your pass ends, open Plan & credits and buy the same plan again. If you buy it before it ends, the new days are added to the end of your current pass.