As opposed to the Name/PTIN info associated with a particular Preparer # in your Firm Info, which George already addressed...

To change the Preparer (or Staff Preparer) # itself, in the Client Info for each client:

 - either use an F3/Filter (pre-built for Preparer, build your own for Staff) and go into Page1/client Info to change EACH ONE individually (not a great solution if there are more than a handful, just from the time it will take),

OR

 - set up an ODBC connection for *each* year/module combination that you need to change.  Open Data1/Client Info file for each, find-and-replace <old #> with <NEW #>.

Robert Kirk

LTUGtools