The free Adobe Acrobat Reader is a PDF viewer and does not allow to modify PDF files. Rotating a PDF and save changes would require to save a modified version of the PDF file, this is a premium feature available in Acrobat DC.
PDFsam 3.1.0 is out
PDFsam Basic 3.1.0 has been released today. You will find the new PDF Extract module, page selection in the PDF Rotate module, an upgrade to our PDF engine with bugfixes and performance improvements, and finally you can now use PDF files generated by one module, as input for another one with just one click.