I started to say you can't, but my dog doesn't snore as much as he used to and I am trying to figure out why....Oh, he has lost weight, and we have changed his food. Some foods can cause allergies and can make a dog a bit stuffy causing the dog to breathe through it's mouth when lying down, hence the snoring.
Now there used to be a real competition between my dog and my husband as to who could snore the loudest. My husband also lost weight plus got a CPAP to wear at night. It is much quieter and I can actually sleep through the night.