Power shell search one column of a csv file and replace text in that column

I have a huge CSV file.

Column J has number which represents states.

I would like to search through column J of output.csv and replace the number with the state name.

     J

Becomes

   J

State

NC

TN

NC

SC

I have tried several methods that seem to do noting or erase everything in my csv file or at best searches every column and if a phone number has 210 in it, it changes it to SC.

Can any one point me in the correct location?

Thanks!

R White