In large soup pot, melt butter; add vegetables and garlic and sautee until tender. Add chicken broth, cream of chicken, and milk and whisk until smooth. Add bay leaf and bring to boil. When boiling add linguine and chicken and boil 8-10 minutes until noodles are tender. Thin with water as needed as pasta starch will thicken soup as it boils. Taste soup and add salt and pepper as needed. Simmer 15-20 minutes to blend flavors. Remove bay leaf and garnish with parsley.
Generally, one cup of water is enough to thin the soup, but feel free to add more if needed. If soup is over-thinned, add milk until desired consistency is reached and season lightly with chicken bulion to even out flavors.
I boil my chicken while I'm preparing the veggies and sauteeing them.