Hi pavan2185, HImba88 hit some pretty good points in his reply, so I'll reiterate that it's up to you whether it's a worthwhile idea or not, and really only you can make this decision.
A word of caution, I've seen students reschedule and reschedule and reschedule. Once you've done it once, you may be tempted to do it again. If something important comes up, then by all means reschedule. If it's just a question of studying more, then be aware that most people don't feel ready for the test on test day and would always want one more day of studying. However, just be sure that if you're rescheduling it's because you will actually study more and get a higher score. And of course, you don't need to convince me or anyone else, you need to convince yourself. There's nothing wrong with rescheduling, just make sure it's for the right reasons if you do.
Best of luck!
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