メモ形式にして、郵送、Fax, emailでしたの文を送れば良いと思います。尚、最後の"Enclosure"は、郵送の時に手紙の他に何かを同封する場合に使います。もし、メールで送る場合は、I am sending you a copy of a ticket and a boarding pass as an attachment. をどこかに入れて下さい。
Date: February 25, 2002
To: United Airline Customer Services
Re.: Request to adust my mileage accumulation
As we discussed on February 25, 2002 over the phone, I lost a boarding pass for my ticket issued for flight # 123 from NRT to LAX.
However, I have a copy of the ticket for this flight and I would really appreciate if you could add the mileage which would have been earned for this flight to my mileage accumulated for account # 1232123.
If you have any questions, please contact me at (telephone number).
Thank you ,