Assuming your subscriptions are directly with each channel:
You would have to log into your accounts for each service and change your passwords on each. Make sure not to share the new passwords with the kids
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
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Ultra 4800 | Streaming Stick 4K+ 3821 | TCL Roku TV 43S245/C107X