First of all....u hav made a big mistake by registering the option u r not interested in.......
During real time allotments,a specific range of rank would be called to the venue,where the students present there register and the allotment list is being published at the same time,the students present there take admissions and the students whose names is not there in the list should not worry as they can see their waiting list status online and they wouldn't be needed to come to the campus to check whether they hav got admitted they could check online, the students who get admission in the first 3 allotment could see their status online...
now i could only say that u could hope to get ur desired branch,i couldn't assure u that u would get upgradation...keep hope and pray...
another way is u could cancel ur admission(if u don't get upgradation to the course u like) and would get the refund if u cancel within the period specified by the officials....