(Name of your company/entity)
(Title of the Client whom you are writing the letter)
(Client’s name of the company/entity)
Dear (Title of the person you are addressing),
This is with reference to [talk here in detail about the issue you want the client to be aware of. Make sure it’s short, simple and crisp. Don’t unnecessarily brag and get diverted from the topic. Keep in mind your explanation should be understood by the reader without much stress to his brain. Don’t make him feel uncomfortable with what he reads. After all you want the reader to resolve your woes].
I would therefore like to request you [talk of the corrective measure which will make you feel more comfortable. Also let him feel that the urgency is a real one].
I am hopeful that you will do the needful at your earliest convenience.