Worthington National Bank is expanding in the Burk Burnett building, at Fourth and Main streets, in Sundance Square. The bank occupies the first floor for its operations but will soon take over the second floor, an addition of 4,445 square feet for offices, Worthington said. The expansion comes nearly a year after the bank opened there. Worthington's part of the building has been closely restored to the original bank that occupied the space in the early 1900s.