How do you increase the number of rings before voice mail cuts in?

New AnswerOn some newer phones (Blackberry, Android, iphone, etc) it's possible to adjust the number of rings required before voicemail takes over.

The instructions how-to depend on the phone you own.

Feel free to ask your question again, but include the make and model of your phone.

Previous AnswerI don't think it is even possible to increase the number of rings before the voice mail cuts in. But if you get a new phone it might have a different number of rings before the voice mail cuts in.