1. A system comprising: a printing apparatus; and a post-processing apparatus, wherein the post-processing apparatus includes: a processor; and a memory storing at least one program which, when executed by the processor, causes the post-processing apparatus to: perform post-processing on a product printed by the printing apparatus, and transmit, to the printing apparatus, instruction information including a first instruction to cause the printing apparatus to perform re-printing processing on a first job subjected to print processing performed by the printing apparatus and a second instruction to cause the printing apparatus to perform re-printing processing on the first job preferentially, wherein the instruction information includes job information identifying the first job, and wherein the printing apparatus includes: a processor; and a memory storing at least one program which, when executed by the processor of the printing apparatus, causes the printing apparatus to: store information about at least one print job in a storage; receive, from the post-processing apparatus, the instruction information; identify information about the first job from the information about the at least one print job stored in the storage based on job information included in the instruction information; and perform control in such a manner that the printing apparatus performs the re-printing processing for the first job preferentially over print processing for a second job for which printing has not been completed, based on the identified information about the first job and the second instruction.