OnCheckStateChanged,unchecked box function?

I am making some options with checkbox,when you have selected one checkbox and select another one in same category,the first one need to go unchecked and i am saving this to a variable.
But its saving the variable to true from the first select.
I read the variable when a button is pressed.
What function can i use to set tha variable to false when is automaticaly unchecked?

I am new at unreal engine so i wos looking for something complicated but it wos realy simple…