I do running as well as the job and I used to get knee problems when I was on a big round or did overtime. However since I've changed footwear and become more aware of how I walk/run I no longer have any knee pain at all.
I wear the trainers for work, the CAT ones originally but now we have even better YDS ones which are a little more bulky but waterproof. I always take out the inner soles so my feet are a little closer to the ground. Don't believe the myth that more cushioning is better, it is not. The more cushioning you have, the less you are aware of your walking style. I seriously cannot walk in the boots, I gave a new pair of magnum boots away as the heels were so high I couldn't walk properly. Could feel it hurting my back straight away.
Look up 'barefoot running' or barefoot walking, it means changing your style, landing on the mid/front foot instead of the heel when running. When walking you still land on the heel but make an effort to push off with your forefoot and try to feel your individual toes when pushing off. Try and be light on your feet, when you go up steps you naturally use the front of your foot and this is better for your knees.
As the other poster said, turn without your feet being planted on the ground. I have got in the habit of turning on one foot with only the front of that foot on the ground. Be careful getting out of vans the combos are too low. Turn in your seat first before putting both feet down and pushing yourself out. dont rush and twist putting pressure on your knees.
If you want to practise the barefoot walking out of work get a pair of vivobarefoot or merrell barefoot trainers, they will force you to walk correctly, as when you walk wrong in them your heels will hurt in no time.