Undo changes in a subform

[odrap]

I want to have the possibility to undo some changes on a subform by clicking a button .
I know that moving the focus from the subform to the mainform has as consequence the the change in the subform is saved and cannot be undo.
Is it possible to have a button on a subform that ,when clicked, can determine the current row in the subform and perform an undo of the changes in this row?

 

[RuralGuy]

If your SubForm is in Datasheet or Continuous Form mode then the record with the focus is also the current record. Moving from one record to another saves any changes to the record you are leaving. Once saved, as you pointed out, then UnDo no longer works.