As you have mentioned the Sastra university in the below comment so I am mentioning the admission process:

Candidates will be given admission to B.Tech programmes in Sastra University for 2 streams.

• Under stream 1, 70% seats will be filled and for that candidates, JEE Main 2018 scores and 10+2 or equivalent examination normalized scores will be taken into consideration
• Under stream 2, remaining 30% seats will be filled and for that candidates' normalized scores of 10+2 or any equivalent, the examination will be considered

For more information you can check out the link given below:

• https://engineering.careers360.com/articles/sastra-university-btech-eligibility-criteria

Puneet if you are talking about giving JEE Advanced exam without passing JEE Mains exam then it is not possible. You need to appear in JEE Mains exam and get marks above the minimum cut-off made in order to become eligible for JEE Advanced exam. Like this time in JEE Mains 2018, the minimum cut-off to be eligible for JEE Advanced exam is:

• General category: 74 marks
• OBC category: 45 Marks
• SC category: 29 marks
• ST category: 24 marks

If you have a query about appearing in any of the other exams then you can mention in the comment below.

Feel free to ask if you have any more queries. All the best!!