If you are not satisfied with your GMAT score, or maybe the Business schools you are applying to have given you some indication that your score isn't quite what they'd like it to be. In such cases, students can think about or retaking the GMAT test.
Sometimes it is necessary to take the GMAT test more than once, like when a management school asks you for more recent scores than what you have. However, unless your scores seem unusually low compared to your performance in the practice tests, or if you have not been able to perform well because of a sudden illness or similar exceptional circumstances, it's advisable not to succumb to the temptation of repeating the test. This is because, given the nature of the test, it is unlikely that your scores can substantially improve.
If you repeat the GMAT test, your scores from the latest test date and the two most recent test administrations in the last five years will be reported to the institutions you designate as recipients. In any case, you cannot take the test more than once in the same calendar month, even if you have taken the test and cancelled your scores.
For official details on GMAT Exam, visit: