Please be advised - changes made this way will not carry over into the EHR. This is a workaround, and any changes to Active chart demographics should still be made in the EHR. Any changes made in this manner to active charts will be overridden the next time the patient's EHR chart is updated/ saved in any manner.
find and copy the Duplicate patient's ID
navigate to Billing → + New Superbill
select Add Patient
search for the duplicate ID → select the duplicate chart
select Edit
add your marker ("DUPLICATE", "DO NOT USE", etc) in front of the patient's first name
Save the demographics
Close the page (we don't want to actually create a new superbill - closing this window will ensure one isn't created)