Hello Vinayak,

IPU CET is the entrance exam to the Guru Gobind Singh Indraprastha University (GGSIPU). IPU CET application forms have been released by GGSIPU on March 22, the end date has not been notified except for B.Tech Biotechnology for which forms have to be filled by April 29. From 2019 IPU CET will not be conducted for admissions to B.Tech courses except Biotechnology. The admissions for all other B.Tech programs will be done through JEE Mains paper 1 marks. 

As for your question, sorry to say but since no correction window dates have been made available, you won't be able to change your preference. You will have to refill the application form

For more information, follow the below link:

Https://engineering.careers360.com/articles/ipu-cet