It's Amisha, not Lara in Aap Ki Khatir

Priyanka and Lara were known to be good friends in Bollywood, since the duo kicked of with Suneel Darshan s Andaaz. But now when Darshan wanted the duo to work again for his forthcoming film Aap Ki Khatir, Lara turned down the offer. She was supposed to play Priyanka's sister in the film.
Not being able to manage dates is one official reason given by the actress who perhaps seems insecure about being in the same frame with Priyanka. Everyone aware knows the fact that Priyanka and Lara started their career at the same time but now Priyanka has kind of outshined Lara.

Director Dharmesh Darshan approached Amisha Patel subsequently, who had no issues to step in. However, Priyanka is not aware of change. She explained that she never had any problem working with Lara. Lara is very good friend and they enjoyed working together during making of Andaaz. She has no issues working with Lara again. Nevertheless she is looking forward to work with Amisha.