Relookup Field Contents
Copies new values from the lookup source field into the records that make up the current found set.
Relookup Field Contents [No dialog; <table::field>]
Perform without dialog prevents a dialog box from displaying when the script step executes that lets the user confirm field information.
Select Go to target field or click Specify to specify the field that is the target of the relookup operation. FileMaker Pro moves the cursor to the field you specify. This must be the match field for the relationship upon which the lookup is based, not the Lookup source or target field. If no field is selected, Relookup Field Contents returns an error code that can be captured with the Get(LastError) function.
This script step is also supported in web publishing and in a FileMaker Server scheduled script.
Calculation fields cannot be used for the Relookup Field Contents command. If you use the Relookup Field Contents command, and you're using a calculation field as the matching value, you must specify one of the input fields for the calculation as the field parameter for the Relookup Field Contents.
When you use the Relookup Field Contents script step, the data must be committed first before the operation is performed, or you may get unexpected results. For example, if a field value is modified and a relookup is attempted before the data is committed, then the relookup search will be based on the old data rather than the modified data. (For more information about committing data, see Committing data in records.)
Originated in 
FileMaker Pro 6.0 or earlier
Show All Records
Go to Layout [“Data Entry”]
Go to Field [Table1::Invoice Number]
Set Field [Table1::Invoice Number; Max(Table1::Invoice Number)]
Relookup Field Contents [No dialog, Table1::Customer ID]
Related topics 
Script steps reference (alphabetical list)
Script steps reference (category list)