How to undo last deleted page without losing all unsaved modifications?

Thanks, but let me explain my case why it is easier to use the original file rather than save my latest modifications including mistakenly deleted page.

A taxi international company is now using e-receipts instead of hard copy. Unfortunately, the receipt via email should take up one page but now spread across three pages. Additionaly, there are more pages prefixed to said email because my manager who took this taxi ride forward me said email.

When I am used to hard copy receipt, I am now starting to add processing to such email to extract the receipt information. When trying to accomplish a task within same time as hard copy receipt, I  mistakenly deleted a page pertinent to receipt data.

The file I refer to has 4 pages in following order:

1. Email from secretary of my Manager
2. her forwarded Email from my Manager  occupies most of the page and last few lines are the email from taxi company
3. receipt information on price amount
4. receipt information on mileage
5. Taxi company Logo

To extract receipt data, I need to delete Page 1, 4 and 5.

After deleting Page 1, Page 2 came up next which is Email content of Secretary and Manager; I did not remember the last two lines of Page 2 contains Header of Taxi Email,  I mistakenly deleted Page 2 which also contains email from Taxi Company.

METHOD 1 (use original file to recover deleted Page)

IMHO, the minimum steps are following:

1. Save modified file containing deleted Page 2
2. Open saved file which is missing Page 2.
3. Open original file which contains all Pages.
4. Drag tab (original file) out of the Acrobat window via mouse for new instance.
5. Click on Thumbnail of Original File
6. Drag Page 2 into Window of Saved File
7. Save Modified File

METHOD 2 (use original file to redo delete Page 1 and 4)

1. open original file
2. delete Page 1
3. delete Page 4
4. delete Page 5

For said file, IMHO, it is easier to redo the deletion rather than recover page from original.

For file with numerous pages and pages to delete are complicated, I will recover page from original.