In a large sauce pan combine chicken broth and water. Add salt.
Bring to a boil then add chicken thighs.
Boil uncovered for 20 minutes.
Place a large pan over medium heat. Add olive oil, chopped onions, garlic, carrots and celery. Saute for 5 minutes until soft.
Transfer to soup.
Remove chicken and shred. Return to soup.
Add pasta and corn. Cook 15 minutes at a low boil until pasta is soft.
In same large pan melt butter over medium heat. Whisk in flour and cook, whisking constantly for 1-2 minutes until barely turning golden. Add 1 cup of the soup broth into the flour mixture, whisking continually until well blended. The whisk in heavy cream. Transfer into soup pot, stirring until blended.
Add salt, pepper, additional seasonings. Bring back to a boil then serve.