Dear Sirs, In order to try and encourage further business with your enterprise, we cabled on the 23rd instant submission to book further 500 kilos of Isoniazid(西药原料) as per your Sales Confirmation No.93SSE0296. We are now in possession of your cable of the 23rd instant accepting the additional commitment and we are arranging for the necessary increase and amendment to our previous L/C No. 20913 to be transmitted to you by cable in accordance with(与…一致) your request. We are glad to have been able to place this further business with you and we hope we may in turn receive enquiries for our various exports in the near future. Also, we wish to notify you that your cable which was dated the 23rd reached us this morning, namely, Thursday the 24th instant and it is, therefore, physically impossible for our reply to reach Thursday 5 pm your time as requested in your cable. However, you should receive our cable reply by 9 a.m. Friday the 25th. Yours faithfully, Peter Jones Purchasing Manager What is the primary purpose of the letter? To advise receiver of ______.