I have got ill and I want have rest and defer my two exam on a convenient time.

I have got ill and I want have rest and defer my two exam on a convenient time. I have booked an 
appointment on Monday 24th to see a doctor in person which I booked during 18th June . The reason for my illness is sudden change in final exam schedule and heat warning. The initial reason to defer the 
Exam as I had stress that 2 exams were on same 
date so I thought it was under conflicting category 
of reason to defer an exam. Now present I want to 
defer is due to medical reason and I would like 
submit a medical document during next week. 
I want this information to written in mail to submit.