What services can be stopped so password can be changed either via command line or rpd upload without locking db account?
You can do this via the exportserviceinstance ,listconnectionpool, importserviveinstance & updateconnectionpool commands. Robin's blog describes the process in detail:
https://www.rittmanmead.com/blog/2016/12/source-control-and-automated-code-deployment-options-for-obiee/