Sampadajahagirdar, Just ask the other university for a new I-20 and proceed with that for ds 160 , visa app etc. There is nothing wrong in having more than 1 I-20 as far as I know. Also you can always return the old I-20 and refute your offer of admission at the other university.
Sampadajahagirdar, It's more complicated than just chucking the I20 and starting afresh. Your SEVIS record is only accessible by one university at a time. You have to contact both universities, the first university should approve the transfer of SEVIS record to the new uni, and then only can the new Uni even have access to your SEVIS to print a new I20 document to send you. Then you fill in a new DS160 document updating necessary fields, and you move forward with booking a Visa appointment.
Sampadajahagirdar, But always remember to preserve all copies of your I20. Old, new everything, till your F1 Visa is done in the sense for all 2/3/4/5 years you're there, keep all the variants of your I20 documents.