I don't have a reason that would be considered "good" to deffer it, just wondering if it's possible and how to go about it. I have Aswani for summer school.

Medical note. However in some courses (such as Organic Chemistry), you don't have to write the midterm, so your final exam is then worth 75%. Email your professor and ask how the course is structured.

Death in the family with a death certificate is the other.

Just get the exam over with now. Postponing it means you forget the material and do worse.

My friend had a midterm postponed for a trip.

Just ask the prof. Some professors are really strict about going through the Dean's office, but I've heard that some professors prefer dealing with that kind of stuff on their own. The sooner you ask the better because they won't suspect that you're just not prepared. But like Lorend said, it's so much easier to write the exam when it's scheduled and not have it deferred.

If you are sick and want to get a midterm deferred, go to a doctor in mcmaster campus health centre or a walk in clinic in hamilton or elsewhere, and have them fill out a "Mcmaster University medical note" which is available for download on the faculty office homepage (for each faculty), once the doctor fills out the note indicating you were ill, take it back to your faculty office. They will inform the instructor via email that you were sick on (so and so date) and you should be excused from the midterm. Most profs will add the midterm weight to the final exam then, making the final more heavily weighted. A few profs will offer a make-up midterm at a later date.