If you're calling from your office phone, you can dial *67 to block all caller ID information, but that is probably worse because the caller ID will then read "private" or "blocked", telling the person you call that you are purposely trying to hide your identity. Anyone who answers a call like that deserves what they get. You could have the phone provider change the caller ID display... but to what? People today just ignore calls from people they don't know, waiting to see if they leave a message. At least if the people see who is really calling (your agency), they can answer knowing who's calling. Those that actually answer won't be totally surprised and defensive. I personally just use my name on my caller ID.