Can you dilute a protein shot?
Since those contain mostly collagen protein, which is an incomplete protein and has a very low amino acid score, you'll get very little protein from them. You can dilute them if you want, but there's no point wasting your money on them. Drink half a cup of skim milk and you'll get as much protein and it won't cost as much or taste bad.
Please note: I AM NOT A DOCTOR. If you want medical advice, talk to your doctor. Whatever I post, there is probably some surgeon or other health care provider somewhere that disagrees with me. If you want to know what your surgeon thinks, then ask him or her. Check out my blog.