There are 2 rotation options in Soda PDF.
In the View Tab, you will see a Rotate view option. This option will rotate your document 90°. This rotation is superficial and does not actually modify the document in any way. This means that even if you save the file when it is opened the rotation orientation will not change.
To actually rotate a page, open the Page Tab select the needed page, and click on Rotate.
To select several pages you can hold the Ctrl key and click on the pages. You can also select a page range or all pages in the menu.
When you save your file, the changes will be retained.