https://www.cesarsway.com/dog-training/ ... g-with-cat
empower the cats by lowering the energy of the dog. That means that whenever the puppy is around the cats, he is in a low-level energy state. That means the puppy has to be vigorously exercised before he comes and meets and greets the cats. That way, the cats will begin to sense a softer energy coming from the puppy.
Redirect negative behaviors that your dog directs at your cat. This includes rough play and barking. Give your pup another activity or do some obedience training with it instead of letting it focus on the cat.
Try to avoid scolding your dog in this circumstance. Keep the situation positive and your dog is more likely to have positive associations with the cat in the future.
Reward and praise your dog for good behavior around the cat. This can include friendly behavior or simply ignoring the cat. Make it so that when the cat comes into the room it's enjoyable for your dog to treat the cat well, not to be aggressive or to attentive to it.
Say, "Oh, look, Puppy, Kitty's here! Yay!" and sound very happy. Then give the dog a small training treat. Your dog will soon learn to associate pleasant feelings with the cat.
good suggestions too, especially about the "Leave it" command.