Avoiding a phone call is not hard in the era of caller ID, but avoiding someone while still leaving a message is harder. Place a call to someone and connect directly to voicemail using a free service called Slydial. Slydial allows you dial a special number from any landline or mobile phone and connect directly to an individual's mobile voice mail without taking a chance that the phone will ring. Once you connect, leave a message that will be sent directly to the person's voicemail inbox.
Dial the special Slydial number available from the service's website. You can use a mobile or landline phone.
Go through the prompts and enter the number for the phone you don't want to ring.
Record your voicemail message and disconnect your call when finished. Your message will be sent to the recipient's voicemail inbox.