Hi,
If you go to the hierarchy and grab the page2 subforms and drag then over page1 in the hierarchy view and release. Designer will move the subforms to page1 and place them at the bottom. Once page2 is empty, delete it.
Check that the page1 pagination settings are set to "continue to filling parent. Also check that page1 is allowing page breaks in content.
The next big change is that page1 will need to be set to a Flowed layout (Object > Subform palette). This is going to move objects around according to their position in the hierarchy and over to the left of the page.
In design view and preview you should still have two pages. You may need to work with subform dimensions and margins to get it looking the way you want.
Lastly, in your script when changing presence use "hidden"; which will not only hide the subform from the user, but also free up the space for lower subforms to move up.
Niall