A program extension is intended for students who are unable to complete their degree program by the completion date indicated on the I-20 or DS-2019.
If you are currently maintaining status and making normal progress toward completing your degree but are unable to complete your program within the specified period on your I-20, you must request an extension prior to the expiration date. Failure to do this will be a violation of your status.
An extension must be based on a documented illness or compelling academic reasons, such as changes of major or research topics, unexpected research problems or credits lost in transfer of schools. Delays caused by academic probation, suspension or oversight are not acceptable reasons for program extensions.
The period of validity of the visa in your passport does not affect your stay in the U.S. It simply refers to the period during which you may enter the U.S. The notation "D/S" means you can stay in the U.S. no later than the date specified on your I-20 for the completion of your program of study, as long as you are enrolled at the university and have not violated your student status.
To request an I-20 extension, your academic advisor must email the International Admission office with your reason for failing to complete your studies within the specified period on your I-20, the number of hours you have to complete.