Hi @scarlson,
Could you please share a screenshot of your first page within your app?
Could you please show a bit more about your scenario?
More details about the Update function in PowerApps, please check the following article:
Update function in PowerApps
In addition, I don't think the Update function could achieve your needs in PowerApps, please take a try to achieve your needs with the UpdateIf function. I have made a test on my side, please take a try with the following workaround:
Set the OnSelect property of the Button (Next Button) control to the following formula:
UpdateIf(Table1,Email=Form1.LastSubmit.Email,Form2.Updates);Navigate(Screen4,ScreenTransition.Fade)
Note: The Table1 represents the Excel Table data source within my app. The Form1 is a EditForm (whose Display mode is in Edit) within my first pape, the Form2 is a EditForm (whose Display mode is in Edit) within my second page. The Email is a column in my Excel table. The Screen4 represents next page.
More details about the UpdateIf function in PowerApps, please check the following article:
UpdateIf function in PowerApps
Best regards,
Kris