We'd need to know what the RAD is being used for 1st.
I'll assume it's a RAD for an ACD path.
Look in the path and find the directory number of the recording.
That directory number could be a hunt group or an embedded VM port (or an external device)
If it's a hunt group, find the member(s).
Next go to Voice Mail -->> system greeting -->>VM Greetings.
Find the port that is associated with the RAD and look up the greeting. It should say "RAD Set Greeting X"
Next go to Voice Mail -->> system greeting -->>VM RAD Greetings
That will show you the greetings you have to change.
Ralph