How to copy data from text field to lookup field?

How to copy data from text field to lookup field?

I built a new form in Creator with a State lookup field which relates to a State table that contains all the US state codes.

My problem is that the contact data I need to import from Excel has the State data as a text field so when I went to import the data the records fails on a data mismatch regarding the state field. 

After reviewing other similar questions I created another field to store the text state code value but I can't figure out how I can bulk update the real state code field (that's a lookup type) with this temporary state code field (which is a text type).

Anyone know how to do this or if there's a better way for me to load the state text codes into a lookup field?

Thanks for your help.

Jim K.