Was the original question involving a professional service that would print many copies of the document and do a professional binding? If so, then printing on your own printer is not an option here.
I would not want to print out 20 copies of a 300 page document [150 sheets of paper each] on my laser printer, which is no a duplex printer. I would not print out a single copy on my duplex inkjet printer either.
It is all about the scale of the print job and the professional looking binding. That is what seems to me the issue here. The person needs the blank pages at the end of his document to fit the needs of his Professional Printing Service. He is not going to do the printing at home, where he can just add unprinted sheets to the stack of paper coming off his printer.
Sure, there are a lot of printers that can do two-sided printing or odd/even printing, but that was not the issue here. I bought a duplex inkjet to save money on paper. I would like a duplex laser printer as well. But I would never use my printers to do a production run for large page count documents. I would use a print-on-demand service or a local printing service for those "production runs".
Would you want to print off 500 double sided brochures for a LO table at a show yourself? Or would you try to get a deal at a printer's place. Just folding them to be a tri-fold brochure, with paper creased already at the folding lines, is too much for me to think about.
It all comes down to the scale of printing and how professional the folding/binding/covers are to be.
He is needing the professional look, in my opinion, and needs the final PDF file to have the extra blank pages at the end of the document. That was the issue, and that is what we needed to give an answer to.
Is there a way to Export-to-PDF or print-to-PDF using internal document controls to create the blank pages with no header or footers? If not then he will have to use some external PDF editing software to "insert" blank pages at the end of the document. Hopefully someone knows how to add/remove/change the header and footer text after a certain point in the document. I remember using some word processor many years ago that allowed that. Just go to page 55 and edit the footer showing on that page and it will be the original one on pages 1 thru 49 and the new one on 50 thru the next change or the end of the document. If that type of thing has been removed due to document file format issues, then it needs to be put back in.
So does any one know how to change the footer to a different text option after 50 pages or so and keep the original footer for the first 50 pages? He needs this for the creation of a PDF file, not a paper version. That is the question here, and not if/how a printer can print his document by some two sided printing method.