I have one requirement like  below

Have one Picklist with 3 values one of the value Named "REQUEST"   if i select" REQUEST" based on this field i want to update 2 filelds  which is alreday existing the values from other 2 fields.

EX:-
 if i select piklist value  REQUEST means update the A,B Fields whatever the data contains from other 2 fileds C,D.
   A  <--------------C
   B <----------------D

Thanks for your time and effort  :)







i came to know this will possible by Trigger or workflow .....Can some one let me know how can i achieve?

Thanks for your Time and effort