We have two small dogs and a dog door in our kitchen. They are great about never messing in the house, but one of our dogs has decided he would rather mess on the patio than in the lawn. How can I "patio-break" my dog and get him to start doing his business in the lawn again so we can enjoy our patio without having to wash it down every day?

Try making a tunnel so they have no choice but to go to the yard itself. If that isn't something you want then hide a small treat in your hand or pocket and walk him out to where you want him to go and praise him with the treat and lots of love. It may take a few days for him to "get it" but he will eventually. Is there anything in the yard he might be afraid of or has something happened in the yard? Is he the alpha dog or the underdog? It might just be that the other dog isn't willing to share the bathroom so try letting them go at different times.