1)Send a call directly to your Voicemail
There are a few people in your address book whose calls you would like to avoid. One way to do so is to let the phone ring without answering; this could be an irritating experience if the person at the other end is persistent and calls again and again. The other way is the smart way! There is an option in Android smartphones to avoid such callers. Navigate to ‘Contacts’ in Address Book. From the ‘Edit’ menu select the option “Send straight to voicemail”. On selecting this option, all the calls from that caller will be forwarded directly your voicemail without ringing. You can also install callmanager apps like Advanced Call Manager, Blacklist Plus or Call Blocker to block selected numbers or to create a profile to block numbers at times when you are busy.