Hello Dheeru, going by our research it seems that you can take the improvement exams for up to 5 years after giving your final exams. These 5 years include 3 chances in which you can take the exams. Also, it seems that you can take your exam in which you were absent in these 5 years. For more information, you can follow this link. This, we hope, will satisfy your query. Have a great day.