Kindly rate this for IELTS band

Q7. A friend has invited you to a party but you will not be able to attend.
Write to your friend. In your letter
* Tell your friend you can’t come
* Explain why you are unable to attend
* Arrange another time to meet

Dear Suma,
First of all, my hearty Congratulations for your well deserving promotion. I’m so glad to hear that all your hardwork has paid off, and surely a party to celebrate your success is something I am looking forward to.
Though I regret to say that the dates on which you are planning for this party coincides with my IELTS Examination. I need to be in Bangalore on May 25th for my exams because of which I wont be able to come to your party.
I was hoping if you can move the dates by a day or two. How about May 27th on Friday? This way, we can continue the celebration over the weekend. Let me know what you think about this or else
if you really cannot postpone the party, we can always meet again when you are free. How about 29th Sunday, I’m hoping that you will be free then. Let me know about your convenient time so we can schedule to meet.

Yours lovingly,
XXX

Hi, I think you misread the prompt a little bit. The prompt is not asking you to reschedule the party, but suggest an additional meeting time, which would be just for the two of you to meet. Customs may be different where you are from - {India I am guessing?} but in the US and the Western countries I am aware of, it would be extremely rude to receive an invitation to a party and then suggest that the host change the date of the party to suit your schedule. If you were very close to the host, still you would say that you are sorry you won’t be able to make it, and at that point the host might suggest changing the party date.