The Easy Way
Go to spooftel.com/freecall
and use their free trial to spoof the call.
The Hard Way
Follow this guide
to setup Caller ID Spoofing w/ Asterisk.
Thanks to the Caller ID Act of 2009
, using Caller ID spoofing for causing harm or defrauding someone is a crime. (Telemarketers are also required by the FCC to use an accurate Caller ID number when they call you.)