FNDCPASS login as what OS user

[laksha]

Apps 11.5.10.2 RDBMS 9.2.0.5 RHE Linux4

We have two nodes

Machine1:PRODDB
osusers:applprod(CM,Ad server),oraprod(Database)

Machine2:PRODAPPS
osuser:applprod(Forms)

I need to change the apps password. I am using metank note 159244.1 (How To Use FNDCPASS to Change The Oracle Users, APPS, APPLSYS and Application Modul...)

NOTE 1: FNDCPASS should be run from the database tier to prevent encryption issues.

If I login as os user oraprod on proddb I cannot find the command FNDCPASS.
Which OS user i should login as for running fndcpass?