Simplify the following text for a Grade 5 native English-speaking person.
Original: She served as official White House hostess and official First Lady of the United States from September 10 , 1842 to June 26 , 1844 , the second of Tyler 's three First Ladies .
Simplified: She acted as the First Lady of the United States from September 10 , 1842 to June 26 , 1844 .