I have two phones lines, but want to convert the second line into the first, since my daughter is at college. I pulled out the phone jack, and there are 6 wires, and four screws they are connected to. The bottom two screws are connected with black and yellow wires (Left and Right respectively). The top two screws has (on the left) a red wire and a blue wire, and on the right, a green wire and a blue/white wire. How do I get this phone line to be on the same as my "main" phone line so I can have the second line disconnected?