Want to change NID wiring to eliminate 2nd phone line
	
	
		I have two phone lines in my house and want to remove one.  Our main line is in the kitchen, and the alternate is in the office & is hooked up to the DSL.  I want to get rid of the alternate line in the office, and change it so that the jack serves our main line & the DSL.  There is a splitter already at the office jack for the DSL.  
How do I make the wire change at the NID?  I can see that there are two screws, one holding red/yellow & a blue wire, the other with green/black & a white wire.  I am confused.  How do I physically make the change to get back to the one main phone line?
Does anything have to change at the actual jack in the office?  I realize that I will have to change my DSL setup with my company to the main phone number, but does anything else need to happen?  
I hope this makes sense and really appreciate any help! :)