Using one of the search methods described in Searching for Patient Profiles, display the patient profile containing the field you want to lock on the View/Edit page.
In the EUID tree, select the component in the SBR containing the field you want to lock.
If necessary, update the value of the field to be locked.
Select the overwrite check box to the left of the field.
Click Commit.
The field is now locked and cannot be edited by updates to system records until the lock is removed.