It is now possible to join two separate PDF file into one file or do the opposite!

All you need is to download a simple software that is available online and for free.  You can get it by clicking  here  

Once you download and install it, all you need is select from the tabs, what you wish to do i.e either split or Merge PDF files.

To SPLIT -

• Select SPLIT and click on (+) sign on the right of the window, you shall be prompted to select the PDF file that you wish to split.
• Then enter instructions of how you wish to split  that PDF file e.g into 2 PDF files of 1 page each or  2 PDF files of 2 pages each e.t.c.
• Remember to select where the new files shall be saved e.g Desktop
• Hit on SPLIT and you are done!

TO MERGE:

• Select the MERGE tab.
• Click on (+) to add a PDF file to the list of files to be merged
• Click on (-) to remove a PDF file from the list (if need be)
• Click on the arrows pointing UP or DOWN to move a file up or down the list. This will create the order in which the merged document shall appear .e.g order of  pages in the new PDF file
• Select where the file shall be saved e.g. Desktop and you are done!

Read on how to convert any document to PDF here: http://www.thetimpata.com/2010/12/09/create-pdf-and-convert-from-pdf-to-ms-word/