I have Nortel system T7316E phones, I was on one phone, and we have 3 lines. I tried to show an employee how to conference a call. I called one of our lines, put it on hold, and conferenced our (2) lines together by hitting conf. button, feature 3, then the other line. NOW... both lines are tied up and when I try to get onto one of the lines, it won't let me and says "line in use" for both lines. HOW can I release them. I Can'e even get onto them??? PLease Help me!