# Editing a Registered Expression Function

You can edit the script or other details of an expression function that you have saved and registered in Spotfire Analyst.

## About this task

Edit a saved and registered expression function in the Spotfire Analyst user interface.

## Before you begin

You must have a registered expression function in Spotfire Analyst. See Registering a TERR script as an expression function for more information.

## Procedure

1. From the menu, click Edit > Data Function Properties.
2. In the Data Function Properties dialog, click the Expression Functions tab.
3. In the Expression functions list, select the expression function to edit, and then click Edit.
   The Expression Function dialog containing the expression function defintion is displayed.
4. Edit the Script, the Function type, the Return type, and the Category, as required.
   Be sure you specify the correct types, according to the script.
5. Click OK, and then click Close to save and rerun the data function.
   Review the results of the change in any visualization that uses the function.