how do i change number of rings before call goes to voicemail?
I had to contact my service provider and have them change it. Actually, it is set by time to ring before voicemail, not number of rings.
That's controlled by the service provider. My wife's carrier does not allow you to change it. I haven't tried changing mine.
Use a call blocker. You'll hear one ring and they get Vmail.
Separate names with a comma.