Formula and Editable at the same time

Another way of stating what I am trying to do -

  1. If Column 1 is 1, Column 2 is blank
  2. If Column 1 is > 1, Column 2 is a choice from a referenced list
  3. If the user completes number 2. (above), THEN goes back and changes Column 1 to < 2,

I want to automatically reset the value of column 2 to blank. Basically trying to eliminate a forward reference issue to make Valid_If statements easier on the user.