Conditional forwarding sends only the calls you don't answer (or decline) to CallsIn. Your customers still call your normal number.
- Verizon: dial *71 + your CallsIn number. To turn off: *73.
- AT&T and T-Mobile: dial **004* + your CallsIn number + #. To turn off: ##004#.
Your exact codes are in Settings, Phone line and in setup. Test it by calling yourself from another phone and not answering.