Dear …
RE: __(Name of Course/Exam)__
I am in receipt of your notification advising me that I was not accepted to __(enroll in the –Name of course-/write the –Name of exam- /etc.)__this time around. The reason given for my non-acceptance was due to the overwhelming interest of the number of people who applied for this __(course/exam/etc.)__. Needless to say, I am very disappointed that I am not one of those chosen, but I do understand that there is only room for a limited number of people.
I wish to express to you at this time of my continued interest in __(enrollment in this course/writing this exam/etc.)__ and request that I be considered for acceptance the next time __(enrollment/this exam/etc.)__ is offered. I thank you for keeping my application on file and remain hopeful that I will be chosen the next time around.
Thank you for keeping my application active.
Sincerely,