As soon as possible, or no later than six months after the end of the academic session when the course was taken.
In a standard term, students have multiple opportunities to drop a course, or request a late withdrawal. If you miss both of these deadlines, the third and last option to withdraw from a course is to submit this type of petition.
A late withdrawal without academic penalty petition, if approved, will result in a notation of WDR on your academic transcript in lieu of a final grade.
You must provide supporting documentation that details extenuating circumstances which are preventing or prevented you from completing the course (e.g. death in family, serious illness), and missing the deadline to drop a course or request a late withdrawal (LWD). Petitions will only be considered if you have not completed the course (i.e., written the final examination or completed the final major assignment/test in courses without a final exam; and you have not been sanctioned for committing an academic offence, or have a pending allegation of academic misconduct.