You need Adobe Acrobat Standard or higher to edit pdf files.
1) Open your document in Adobe Acrobat (not Acrobat Reader).
2) Click on the “Pages” tab on left side of the page. Alternatively, use the keyboard shortcut Shift + Ctrl + R, to open the rotate pages dialog.
3) Right-click on the thumbnail image of the page you want to rotate. You will have the default choice to rotate the selection or you can choose a range of pages to rotate.
4) Save your changes.
NOTE: The common pitfall is using menu View -> Rotate View -> Counterclockwise and save the document, which will only temporarily rotate, not permanently.