PDF re-format print output

Need a utility program to convert 2 page .pdf files that are formatted to print in 8.5x11 to be reformatted and saved as a 2 page 4x6 .pdf in in an automated fashion. The utility program will need to drop out the "white space" border around the image on the page. See attached file that contains a shipping label that was formatted to print on 8.5x11 plain paper. This 4x6 image needs to maintain its actual size, it is to be used as a shipping label printed on 4x6 label stock. The second page in each individual file will be a packing slip that will need to be resized to print in the 4x6 space. Using one .pdf file at a time or using a folder that contains a hundred individual .pdf's , reformat each individual .pdf and combine them into a single large .pdf print file. The Utility program will be able to create a new unique batch file for up to a hundred individual .pdf files at a time. A summary .txt or .csv file containing all of the individual file names that have been combined into the larger batch to print must also be created containing list of which individual .pdf files were reformatted to 4x6 and combined into which large batch print file.