The fighting between Yuan Shao and Cao Cao ended without any one-sided resulted because Yuan Shao died before either side could get conquered.
However, if one of the two sides actaully managed to secure a victory, what would they do with the other officer? Would they allow a surrender? Take them into their service? Execution? Commoner Status? Would they even surrender or would they be too proud and just commit suicide? Is is the same for both men?