next to the Measure field.Steps for:
See also: Why isn't there a Section for Time in the Insert/Edit Measure Item Window?
1. Double-click the caption for the measure item in the view.
OR
1. If the Properties
window for the measure item is open, click the Browse button next to the Measure field.
2. In the Edit Measure Item window, select one or multiple measure items to edit.
3. Use the Measures drop-down list to select a new measure for the measure item(s).
If needed, use the search button 
to open the Select
Measures window. Use the window to search for particular types of
measures, make your selections, and then click OK or Cancel when you are
done to return to the Edit Measure Item window.
4. Click Update to update the selected item(s) and leave the window open to change additional measure items.
OR
4. Click OK to proceed with the edits and close the window.
1. Double-click the caption for the measure item in the view.
2. In the Edit Measure Item window, select the first measure that you need to edit.
3. Use the Measures drop-down list to select a new measure for the measure item.
If needed, use the search button to open the Select
Measures window. Use the window to search for particular types of
measures, make your selection, and then click OK or Cancel when you are
done to return to the Edit Measure Item window.
4. Click Update to update the selected item and leave the window open to change additional measure items.
OR
4. Click OK to proceed with the edits and close the window.