Cook bacon in a large saucepan on medium heat until crisp. Add onion; cook and stir for 3 minutes. Add water and potatoes. Bring to a boil. Reduce heat to low; cover and simmer for 5 minutes or until potatoes are tender.
Stir Gravy Mix and flour in a medium bowl. Stir in half-and-half with a wire whisk until smooth. Stir mixture into the saucepan. Add turkey, corn, and sage. Bring to a boil on medium heat. Reduce heat to low; cover and simmer for 10 minutes, stirring occasionally.
