Dear____________,
____________at/in__________on___________ would be a great pleasure to have you attend this event.
I am sure that you will be interested in_______t,____________nd,_______osed is the details of_____________ participation is very important because_____________.
The ____________will begin at____________ do hope that you can make it not,would it be possible for you to drop us a line before_________?Thank you very much.
Best wishes.
____________