Macro To extract Data and place into another document

Hello everyone

I have a small problem which im hoping someone can help me with please??

I have two seperate documents both have two columns, one has a part number and the other has the part description in it, I need to run a macro that looks for the part number in the cost price list test and changes the description to the one from the Numerical list test, then fills the line in red to indicate it has been altered. This will hopefully help in creating one correct document instead of two incorrect documents! I get all the good jobs!!
Ive attached to shortened sample documents the originals go on for about 2000 lines so as you can tell this will be a massive help to me.

Any Help would be much appreciated

Many Thanks

Denzil