Check Cell.Value for identical Value..IF Not Then

I am coding using VBA in Excel. My question is slightly complicated but the function is simple;

I am trying to make a cell follow a parent cell. Let me explain:

   1 A              B              C
   2 29/11/16      30/11/16        1/12/16
   3               30/11/16

Cells A2 thru C2 is the 'parent cell' Cells A3 thru C3 is the 'follower cell'

User will input a date in the 'follower cells' following the 'parent cell' The 'parent cell' is dynamic and will change its properties over time like so:

  1 A              B              C
  2 30/11/16       1/12/16         2/12/16
  3 30/11/16

My problem is that I need to have the 'follower cells' follow its 'parent cell' automatically, like what is shown above.

I have just started coding and I have tried designing various solutions using IF else statement, but that is as much as I know and its getting too complicated for me but I am learning from various sites and trying out codes.

I need help from the experts on this.

Thank you.