Caution:
Removing a subform from the Alternative Subforms list by using the Edit Data Nominated Subforms dialog box completely removes the subform object from your form design. If you want to preserve the subform object but remove it from the choice subform set, you must manually drag the subform object out of the choice subform set by using the Hierarchy palette.
3.
Click the Add button Livecycle button add 2 To add and remove subforms in choice subform sets to insert a new Alternative Subforms list item. You can also drag and drop subform objects into the choice subform set by using the Hierarchy palette.
4.
Use the Up Livecycle button uparrow To add and remove subforms in choice subform sets and Down Livecycle button downarrow To add and remove subforms in choice subform sets buttons to move the new subform entry to the preferred location. Ordering entries in the Alternative Subforms list is important because entries are processed sequentially at run time, and the first entry with an expression that evaluates to true appears in the form.
See also 

To add and remove subforms in choice subform sets