I, Ms Jessica, am drafting this letter to make you aware of the fact that I will not be able to keep up with the appointment which we have approved upon for the check up of my liver. I express severe apologies for this amateurish behaviour on my part and I wish to convey that you shall now dedicate the rendezvous time to any other deserving thing. My college examination has been shifted earlier and I need to work on my studies. Since you intimated me that the check up can be stalled for some time, I wish to postpone it for three weeks or so.
I wish to convey that I am extremely sorry for the time loss. This letter is enclosed with a list of dates which shall be feasible for me for the said check up. Please, go through it and make me known about you preference.