"Set Field [TRANSACTION::City; TRANSACTION::City = "Chicago"]"
Should be Set Field[Transaction::City;"Chicago"]
That worked perfectly. Thanks for the help. I am use to hard coding and the pre-built Filemaker Pros functions are great but I have to get used to them first or at least understand the inner workings of them.
You may want to consider passing the city name as a script parameter and use Get(ScriptParameter) instead of the city name to avoid hard-coding your find.