Change the date a progress was updated

When the progress bar is updated [mostly for awaiting approval/awaiting payment] it would be useful to be able to change the date. Currently the date is set to the date of action which will match the date an email was sent to the client however if they approve but do not pay and the task is updated, the new progress note has todays date rather than the original. this then causes problems when the automatic emails go out asking clients to look for payment request of xyz date but in reality the date they would have an email is the original date