Voicemail - How do you leave someone a voicemail without calling them?

How do you leave someone a voicemail without calling them?

I have done this before but I am having difficulty doing it today.... I want to leave someone a voicemail but I don't want to call them and give them the opportunity to answer the phone. I want to just get their voicemail and leave a message. I have done this before by calling my voicemail, then pressing the button to "send" then typing the phone number (and I forget if I dial 1, hit pound, or anything else special).... please help and tell me step by step how to accomplish this objective... thanks!

Public Comments

you need that persons voice mail access number.
hmmmmmmm, can you not call in the middle of the night, when you know that the cell-phone is off!!! but you still can leave a message...
you might be having difficulty if the person you want to leave a message for is on a different carrier or if they're on the same carrier but in a different area code. in many cases you just won't be able to do it thru the voicemail system try using getabuz.com - you can send messages to anyone regardless of carrier for free.
you need that persons voice mail access number.