Dear Sir John, I am writing this letter to inform you that I cannot carry on with the course in your institute.
Previously, I was working as a graphic designer in a multinational company. Recently, I got promotion in my job because of my hard work and efforts now I am head of designing department.
My senior give me an opportunity and responsibility of the biggest project of our company with a deadline. To complete the target on time I have to engage my whole day in my work due to which unfortunately I will not be able to continue with the course. The way you teach English literature is remarkable but the project requires my attention and obviously, extra sitting in the office.
Along with my native language, English is one of the foreign language which I like to learn. I was in dilemma weather how to manage my study and work. I was muddled, but now I came to a conclusion that I should pause my course.
I would like you to hold my course for some time I assure you I will resume my course as soon as I am done with this project. Yours sincerely, 
Dear Sir John, I am writing this letter to inform you that I cannot carry on with the  
course
 in your institute.
Previously, I was working as a graphic designer in a multinational  
company
. Recently, I  
got
 promotion in my job  
because
 of my  
hard
 work and efforts  
now
 I am head of designing department.
My senior give me an opportunity and responsibility of the biggest project of our  
company
 with a deadline. To complete the target on time I  
have to
 engage my whole day in my work due to which unfortunately I will not be able to continue with the  
course
. The way you teach English literature is  
remarkable
  but
 the project requires my attention and  
obviously
, extra sitting in the office.
Along with my native language, English is one of the foreign language which I like to learn. I was in dilemma weather how to manage my study and work. I  
was muddled
,  
but
  now
 I came to a conclusion that I should pause my course. 
I
 would like you to hold my  
course
 for  
some
 time I assure you I will resume my  
course
 as  
soon
 as I  
am done
 with this project. Yours  
sincerely
,