I dont think this is possible ......
If you're in the United States, dial *67 before you type in the number (example: *67123-456-7890)
hello
This will depend on the phone model and your phone carrier. You can call them to find out how to hide your number.
They can
*67 before # u call
it is not possible in pakistan
On any GSM mobile phone, dial #31# before the number to suppress display of your caller ID information.
yes star 67 (*67) before the number you are calling will block all numbers!
hide your fangs
In nokia mobiles renaming file or folder name with an extension (z.otb) we can hide
It happens when either holder of that number can hide "caller id" (permission from network provider required) OR when international call was made via calling card which does not have it's own number.