Before starting look up the demographic number in the oscar search of the patient that wants their chart blocked.
In the admin/ assignRoleRights to Object screen:
Go to the bottom section of that page and select the user from the drop box. Then goto the bottom of the page and type this in the text box
To block the echart
_echart$<demographicNo> eg. ( _echart$234432234 )
To block the master demographic
_demographic$<demographicNo> eg. ( _demographic$2342342342 )