The feature in question is feature of call control device (PBX) not the phone itself. You disclosed no details about the equipment, thus no way to even guess the answer. I will offer you a three randomly selected answers:
- The PBX may not have such feature at all. It's so old, it's so cheap and dumb, it's not PBX designed for business environment.
- PBX have such feature implemented, but specific license needs to be purchased to unlock it. Your company have no such license.
- PBX have such feature implemented and enabled, but person in charge doesn't know how to configure it.
Remember - this list is not exhaustive. No answer above may apply to yours particular case.