Be specific about the purpose of the event, number of attendees, style of company/attendees, etc. The more an event planner understands about the company culture, the attendees and the budget, the more successful the event will be.
1234, Main Street
Boston, MA 02123
<Recipient Address Goes Here>
Our company is planning a <type of event> on <date> and would like some help planning and executing this event. Of course we want it to be impressive and memorable. There will be approximately <number> attendees and the dress code will be <dress code>.
I understand that you can help us with all the arrangements, specifically: <where help is needed>. Please call me at <phone number> to set up a time to review our needs, your capabilities and how we might make this a memorable event! We are interested in moving as quickly as possible.
encl: <List of enclosed items goes here>