Begin on a warm and relevant note. Also make sure that you follow the appropriate format of writing such a letter. Date at the top left corner, followed by your name, the company that you represent and the address.
Provide a smooth transition from the opening sentence. Then follow the necessary background information for the claim.
Tell exactly what the problem is in a neutral and courteous tone.
Provide a rationale for granting the claim. Ask specifically and confidently for a specific request. Include any benefit to the reader.