Can a challenge be unactivated if you know you know you make a mistake in activating it?

Not if it’s a GOTM or a Marathon Badge.  What badge are you trying to deactivate?

Quinn’s Aquarium.  Thank you for responding.

You’re very welcome!
 
Sorry it was the GOTM that you were talking about since they can’t be deactivated.

Again, thank you for responding so quickly.  I hate to admit my ignorance, but what is a GOTM?

Never mind.  I figured out GOTM (silly me).  I meant a game of the week.

If you are trying to deactivate a Personal Weekly Challenge you should be able to do that.  All you have to do it pick another Personal to replace it with, or just wait until Tuesday and it will deactivate itself if you don’t have another Personal that you wish to do.
 
If’s it 1 of the 2 Weekly Challenges you will just have wait and it will deactivate itself on Tuesday evening.  But you can’t pick another game to replace it with.  Pogo picks those badges, and you can’t replace them with something else.  That’s the same with the Daily Challenges.  Pogo picks them and what we get is what we get.  But they will go away when tomorrow’s dailies are released.
 
Good Luck!!

Thanks so much for your help.  It is greatly appreciated.

You’re very welcome!