Here is my situation:

First, I have a spreadsheet that has shortened names of ~ 100 facilities
along with a corresponding absolute reference code (number/letter mix). For
example, Chicago may have a code like GA123.

Second, I have a master spreadsheet that includes tons of programming with
charts and sorts.

Third, each month I need to pull a downloaded file (spreadsheet 3) from an
external source which has data associated with the facilities. The external
souce uses very long names sometimes, so my master spreadsheet has some
coding that copies the shortened versions from spreadsheet 1 into spreadsheet
3.

My problem has started recently when a few facilities were sold and a few
were bought.

I would like my master spreadsheet to look at the plants listed in
spreadsheet 3 and then match them by code with spreadsheet 1, and then
replace the long version names in spreadsheet 3. If there is a plant change,
I would like for the spreadsheet 1 to be updated automatically with the name
and code from spreadsheet 3.

I know it's a bit confusing, so if you need more information, I can provide.

thanks.