WDClientUser. getClientUser("caf_gp_svcuser") returns logged in user

I am trying to get a service user in a Web Dynpro Callable Object so that I can navigate through the currently running Guide Procedure process, but when I execute the following:

IWDClientUser administrator = WDClientUser. getClientUser("caf_gp_svcuser");

it returns the logged in user instead of the service user. I can get a service user?