Sunita Williams stuck in space: Why can't NASA send out a spacecraft and bring her back?

Sunita Williams stuck in space: NASA is not in a rush bring Sunita Williams and Butch Wilmore back to Earth. Boeings Starliner returned to Earth uncrewed on September 7 this year. Sunita Williams and Butch Wilmore will return in February via a SpaceX Crew Dragon spacecraft. But the question still arises- Why can't NASA send out a spacecraft and bring the astronauts back?