If a candidate discovers any Mistake in the BITSAT Application Form submitted by him, he can apply online second time and send a letter to admission office BITS, Pilani mentioning the earlier application number which will be cancelled. In such cases, the second application has to be accompanied by a fresh application fee.
You cannot edit application Online once submitted. If the mistake is minor, you can send a written signed request for the correction. However, if you want to change the center preferences, you will have to apply afresh with a new application fees.