Run macro on change within target range | Change (ByVal Target As Range)

I'm working with the Worksheet_Change(ByVal Target As Range) event.

I wanted to run a macro if either on of cells A1 or A2 are changed. So the target range is set to [A1, A2]

Then, if A1 is changed, I want to clear A2, or the other way around (A2 is changed: clear A1).

Now the problem:

If A1 value is changed. the macro clears A2. That's seen as a change in A2, so it clears A1, which is a change, etc...

I'm sure it's something simple, but I can't see how I can have cell A1 be changed without triggering the change macro if A2 is being cleared.

Anyone who has experience in this?