No, you can't modify the answers on JEE Advanced Optical Response Sheet.
Since the bubbling on ORS for JEE Advanced is done using only black ball point pen, candidates cannot modify the answers once bubbled.
Yes, you are eligible to enrol yourself for JEE Advanced 2017, provided you clear all the eligibility criteria.
A candidate should NOT have been admitted in an IIT/ISM (irrespective of whether or not he/she continued in the program) OR even accepted the IIT/ISM seat by reporting at a institutes reporting centre in the past.
The Results to JEE Main 2017 will be available by the end of April.
The Application Process to JEE Advanced will begin on the 28th of April and end on the 2nd of May 2017.
Yes, it is compulsory. If a student is absent in one of the papers, then the candidate will be considered as absent from the JEE Main 2017 examination.
Do not wear unnecessary things such as rings, chains, bangles, ear-rings or a modern watch. A simple analogue watch is permitted so that you can have the estimate of time.