Hi!

According to the latest notification by CBSE, you can appear for improvement in one subject in the Compartment exam just after your main exams. The better of the two scores will be considered as final. However, if you want to improve in more than one subjects, you'll have to wait for an entire year and apply for improvement as per Rule 44.1 of CBSE which states that a candidate can appear for improvement in succeeding year only. The changes were made to reflect the New Education Policy of the government. Hope this helps!