Making references and closing remarks
  26 August 2003
To remind you of the previous lesson, here is the letter from the last lesson when we talked about subject and enclosure.

 Payathai Mention
 Apartment 5 Payathai soi 3
 Payathai Bangkok
 10400

 13 August 2003

 Khun Akom Kanchanasak
 J&B Associates
 13 Nakorn Chaisi Road,
 Dusit, Bangkok
 10300

 Subject: Rent Contract Renewal

 Dear Khun Akom,

With reference to your letter on 11 August 2003 regarding my new rental contract, I would like to make some amendments. Please refer to the enclosed article with special attention to the paragraph 5. I noticed that the rent has increased from 8,000 to 9,000 baht a month. I was not informed of this change prior to this. Could you please check if it is a typing mistake or that I was not aware of the new terms?

 I would appreciate your immediate reply.

 Sincerely yours,

 Mana Meesak
 Enclosure: Rent contract 2003

Mana is replying to Akom's letter, so he has to refer to it. He uses 'with referenec to'. You can also use these expressions:

Regarding you letter of Aug 11...
Thank you for your letter....
Following our conversation this morning, ...
In reference to our last meeting....
Reference is made to my previous enquiries.

At the end of the letter, you can express your appreciation or request further actions. For example:

Thank you for your help.
Please do not hesitate to contact me if you require further information or assistance.
Please feel free to contact me if I could help in any way.
Please contact me if you have any questions.

I look forward to hearing from you soon.
I look forward to your reply.

Mana's 'I would appreciate your immediate reply' is rather hush. He demanded that his letter is answered as soon as possible. However, in his case, he might be wronged and the matter is quite urgent. Therefore, his closing remark is better than 'Please reply me as soon as possible'.