DISPATECH:Legacy Properties to New properties

I am trying through dispatch to swap properties but am failing. When I bring a part into the vault, I check it in and then run a dispatch script to rename the part from an old naming scheme to a new naming scheme. Also during that script I want to swap the properties of the Part Number Field from PartNo to fpartno. I setup a variable to get the PartNo from the selected file then in the script I write the variable back to the data. Some parts have multiple configurations and different part numbers. I cannot get the values of each config to populate.

SolidworksSolidworks Pdm enterprise Pdm