Talk to him. Touch him through the kennel door. When he is worked up, turn your back and ignore him. Leave the room for several minutes and re-compose yourself as a neutral person. If the dog has shown repeated aggression to 2 or more tests, discontinue further testing or proceed with caution.
All subsequent tests are hands on, with the dog out of the kennel.
Proceed with caution or discontinue further tests if dog shows threat in any subsequent test. List details of behavior with each area if noteworthy. Stand over the head and reach down over the shoulders to the underchest. Try to get him to enjoy a rolling rub. Play with the dog in an excited fashion.