13. A non-transitory computer-readable storage medium storing a computer executable program, the computer executable program comprising: a receiving step of receiving a print-instruction document including a page layout information, wherein the page layout information is set to a document which includes a plurality of pages, and wherein the layout information includes identification information to identify a sheet number for each page and double-side information to identify on which side of a sheet, a front side or a reverse side, each page is to be printed; a determining step of determining whether or not a specified printer is capable of a double-sided printing; a changing step of performing the changing process, wherein the changing process includes changing a description for the reverse side of the double-side information to a description for the front side of the double-side information and changing a sheet number of the identification information, wherein the changing process is performed for a page in a case that the first-determining step determines that the specified printer is not capable of the double-sided printing; a transmission unit for transmitting printing data based on the print-instruction document changed by the changing unit through a printer driver; a storing step of storing the print-instruction document changed in the changing step when storage of the print-instruction document is instructed; and a reusing step of reading the print-instruction document stored in the storing step and executing printing when the printing of the stored print-instruction document is instructed.
13. A non-transitory computer-readable storage medium storing a computer executable program, the computer executable program comprising: a receiving step of receiving a print-instruction document including a page layout information, wherein the page layout information is set to a document which includes a plurality of pages, and wherein the layout information includes identification information to identify a sheet number for each page and double-side information to identify on which side of a sheet, a front side or a reverse side, each page is to be printed; a determining step of determining whether or not a specified printer is capable of a double-sided printing; a changing step of performing the changing process, wherein the changing process includes changing a description for the reverse side of the double-side information to a description for the front side of the double-side information and changing a sheet number of the identification information, wherein the changing process is performed for a page in a case that the first-determining step determines that the specified printer is not capable of the double-sided printing; a transmission unit for transmitting printing data based on the print-instruction document changed by the changing unit through a printer driver; a storing step of storing the print-instruction document changed in the changing step when storage of the print-instruction document is instructed; and a reusing step of reading the print-instruction document stored in the storing step and executing printing when the printing of the stored print-instruction document is instructed. 17. The computer-readable storage medium storing the computer executable program according to claim 13 , wherein the specified printer is defined by the print-instruction document.