Disable ability to delete a Medical Record Number when registering a patient

When user is registering a patient in EDIS, they are able to delete the Medical Record Number, this causes a subsequent effect of all of the encounters connected to that MRN disappear. No one but Medical Records should be able to merge a Medical Record Number. and NO ONE should be able to delete one. We had this happen in ED when a new user was registering a patient, thought she had made a mistake and in trying to correct her mistake, she deleted the MRN, and subsequently created a New MRN and 2 encounters for the visit. Re: sit 9805462

I would add that this is an URGENT need