Yes, there is an option of branch sliding in PEC. You can change your branch after the second semester (i.e., first year). I know someone who upgraded from Metallurgy to IT. The upgrade is not a difficult task.
Following are a few things that you should keep in mind.
You can definitely go for changing branches in PEC by choosing a branch-like CSE, ECE, or any other of your interest. As for the choice of the branch you should choose the one that interests you.