On July 3, 2013, after the box office success of the first film, Lionsgate CEO Jon Feltheimer confirmed that there would be a sequel to the film, with production beginning in 2014 for an unspecified release date. In September 2014, it was confirmed that Jon M. Chu would replace Louis Leterrier as director. On October 2, 2014, Michael Caine confirmed in an interview that Daniel Radcliffe would be playing his son in the film, and that shooting is expected to begin in December in London. The film was produced by Lionsgate and Summit Entertainment. In October 2014, it was announced that Isla Fisher would be unable to reprise her role as Henley Reeves due to her pregnancy, and Lizzy Caplan was cast as new character Lula to replace her as the Fourth Horseman. The sequel was thought to be titled Now You See Me: Now You Do n't, but it was announced in November 2014 that the film had changed its title to Now You See Me: The Second Act. On January 28, 2015, Henry Lloyd-Hughes was confirmed to play the role of a tech whiz kid named Allen Scott-Frank. On December 22, 2014, it was reported that Morgan Freeman was not going to reprise his role as Thaddeus Bradley, but on January 19, 2015, film director Chu posted a selfie with Freeman on his Instagram, verifying that he would return.

Answer this question: why is there a different girl in now you see me 2? Let's give stream of consciousness first:
This is the relevant information: In October 2014, it was announced that Isla Fisher would be unable to reprise her role as Henley Reeves due to her pregnancy, and Lizzy Caplan was cast as new character Lula to replace her as the Fourth Horseman.
So, the final answer is Isla Fisher would be unable to reprise her role as Henley Reeves due to her pregnancy.