Answered question
I activate my sim card on an account but I did'nt want it on this account but on an other. How to do it?
Probably you will have to order another sim card and activate it on the correct account.
Confirm it with support.
Other answers
Unless I am misunderstanding your question, it sounds like you will need to contact FIZZ since it will likely need to internally reset for you.
You can contact them at https://fizz.ca/en/contact-us