Working with related tables and files > About lookups > Updating lookup values
Updating lookup values
If you change data in the match field of the related table or in the lookup source field for a lookup, FileMaker Pro doesn't automatically update the data in the lookup target field. To update the data, you need to look it up again.
Important  Relookup Field Contents updates all fields looked up by the match field across all records in your current found set. You can't undo your actions when you update lookup values.
To update lookup values:
1. In the current table, use Find mode, or Omit Records in Browse mode, to create a found set that contains only the records you intend to update.
2. In Browse mode in the current table, select the match field, then choose Records menu > Relookup Field Contents.
3. When you see an alert message, click OK.
Note  The Relookup Field Contents command is performed without committing the active record. See Committing data in records.
Tip  You can update lookup values automatically by defining a button to perform the Relookup Field Contents script step.
Related topics 
About lookups
Defining lookups
About relationships
Defining or changing a button