[topic moved to Reader/Acrobat DC for Mobile forum]
How about turning off the Auto rotate feature on your iPad and then turning your iPad sideways?
Open the PDF file in Acrobat Reader on your iPad.
With Document Cloud subscription you will get 'Organize Pages' tool on the left.
You will get Thumbnail view of all the pages in that PDF.
Tap & hold the page which you like to rotate and select the rotate option from the bottom toolset (90 deg clockwise/anti-clockwise)
Let me know if this helps.
It does not help. Rotating orientation is not currently supported.
To use the 'Organize Pages' tool, you would need a paid subscription called "Acrobat Acrobat Pro DC".
Acrobat Reader for iPhone and iPad displays the 'Organize Pages' option in the Tool Switcher, only if you subscribe to the "Acrobat Acrobat Pro DC" subscription service and signed in.
Otherwise, page rotation is not supported, as ed from st. louis pointed out.