Dear Mr. Jackson,
I am writing this letter to inform you that I will have to postpone my stay in the rented apartment contracted for next month. Although I was too excited about the stay, I will have to postpone my plan due to some personal reasons.
Let me explain my problem. Yesterday night my brother was coming back from his work when he met with a terrific accident. I had to immediately admit him to the hospital that is near my place. The doctor said he will have to undergo surgery and will take time to recover. I know that its the time to shift to the newly rented apartment of yours but with the current situation, I will have to stay with my brother. I will have to take care of him and his doings until he gets back on his feet.
I would like to request you to change the contract date from next month to two months from now. I will be readily available to shift to the new home by June. I would be grateful for your consideration. Please write me back about the contract details. Looking forward to hearing from you.
Yours Sincerely,
Ishita
Dear Mr. Jackson,
I am writing this letter to inform you that I will  
have to
 postpone my stay in the rented apartment contracted for  
next
 month. Although I was too excited about the stay, I will  
have to
 postpone my plan due to  
some
 personal reasons. 
Let
 me  
explain
 my problem.  
Yesterday night
 my brother was coming back from his work when he met with a terrific accident. I had to immediately admit him to the hospital  
that is
 near my place. The doctor said he will  
have to
 undergo surgery and will take time to recover. I know that  
its
 the time to shift to the  
newly
 rented apartment of yours  
but
 with the  
current
 situation, I will  
have to
 stay with my brother. I will  
have to
 take care of him and his doings until he  
gets
 back on his feet. 
I
 would like to request you to  
change
 the contract date from  
next
 month to two months from  
now
.  
I
 will be  
readily
 available to shift to the new home by June.  
I
 would be grateful for your consideration.  
Please
 write me back about the contract  
details
. Looking forward to hearing from you.
Yours  
Sincerely
, 
Ishita