It would really help to see some screenshots of your form and it's controls.
However, I can tell you that a rule will not be able to change the values of another control. For this, you're going to want to use JavaScript in the Settings -> Custom JavaScript section.
I will often show/hide a portion of a form based on the selection of a control. And, when the section is hidden, I always want to clear out any data that may have been entered into those (now hidden) fields.
Here's an example:
Image of Form Example
And here's the code:
NWF$('#' + myYesNo).change(function(){
NWF$('#' + myChoices + ' input').prop('checked',false);
});
Every time the Yes/No field is checked, everything in the Choices field is unchecked.
I would also suggest adding a rule to the Choices field (and its label) that says not(myYesNo)
: like this.
If you didn't want to hide the choices, I would expand the JavaScript to test whether or not the Yes/No is currently true or false. However, hiding the choices entire remove the need for that test.