Picking Different Lot than allocated in the Task

We have many lot controlled parts in our organization.    As good as our picking rules are there are cases where it is useful to allow the user to pick a different lot than the one allocated.     By using expections and transaction reason we are able to allow users to pick from a different locator for non lot controlled parts.   This will also actually work for Lot controlled parts as long as the lot that has been allocated is in the new locator you are trying to pick from. 

We can change the lot allocation by editing the move order allocations but would like to be able to in special cases have the warehouse worker pick a different lot.