Start by spreading mayo 1 side of each slice of bread.
In a small bowl, mix the cream cheese, blue cheese, celery, and 2 tbsp of ranch. Spread on the non-mayo side of two pieces of bread. Top both slices with one slice of cheese
In another bowl, combine remaining ranch, buffalo sauce, and chicken. Spoon on top of both pieces of bread with cream cheese mixture and cheese. Top with remaining cheese slices and the non-mayo side of the remaining two slices face down.
Place in a pan over medium heat and cook until brown on each side (3-4 minutes each side). Slice in half and serve immediately.