You can modify an existing ad hoc index in the current schema if it is not yet populated (that is, it has a light pink background in the Status column of the table in the Ad Hoc Index Browser). You cannot change ad hoc definitions if the collection has been built or it is being built.
To change a relational view
Click in an unpopulated ad hoc index and then select the Change command from the Ad Hoc Index menu.
The Define Ad Hoc Index dialog is then displayed. For details about the Define Ad Hoc Index dialog, see "Adding an Ad Hoc Index", earlier in this chapter.