Iphone 5 Conference Feature...
iphone 5, not able to conference in 3rd line, add call greyed out, called verizon, the service in enabled with the carrier, has anyone seen this?
iPhone 5, iOS 6
I've only seen this when there is a carrier account setup problem.
Try restarting the iPhone and then restoring it. If that doesn't take care of it, try contacting Verizon again.