Question

write an application to the principal of your school to exempt you from appearing for half yearly exams as you are down with chicken pox

Answer 1

so here's a formal letter with the typical old format.

216, Ring Road
Delhi
53002

6th January 2019

The principal
xyz school
53002

Sir,
sub: leave application due to chicken pox

I (your name here), of class xyz would be highly obliged if allowed to be exempted from writing the half yearly exam, as for now I am suffering with chicken pox.

And the doctor has advised to take complete rest, which would be good for me and others as well because chicken pox is a contagious disease.

Thanking you
Yours Sincerely
(your name)
(signature)