I have few scenarios for locking the date
If Closed:Won – Date locked
If Stage changed to ‘Closed:Lost’ or ‘Declined’ from Closed:Won then date is changed to the date of that activity and locked again.
If Stage goes from Closed:Lost, Declined or Closed:Won to anything pre Closed Won then date is unlocked and can be edited as usual.
How can I implement the above logic?