Do the following steps:
In the Navigation Pane, click the area that has the custom field you want to change.
On the Tools menu, point to Configure, and then click Custom Fields.
The Custom Fields dialog box appears.
In the Custom Fields pane, click the custom field you want to change.
In the Settings area, edit the contents in the Custom Field Name box or in the Description box.
Click OK.
You cannot change the Location or Writing System(s) selections of an existing custom field.
If you edited the name, but the field label does not change refresh the window, or close and reopen the project.