Setting a point in a Variable Fillet BACK to Unassigned

This one seems obvious but I can't seem to find anywhere to do so. I have a VarFillet that I've been messing around with the get the radii right in the right places.

The only problem I have is that once you give a point a variable, how do you go back and set the same point to have no assigned value? Deleting the value from either value box just sets it to 0mm.

Is there something I'm missing?

Thanks. Lincoln

SolidworksParts And Features