[Your letterhead, if desired; if not, your return address]
[Date of letter-month, day, and year]
[Recipient's first and last names]
[Street or P.O. box address]
[City, State ZIP code]
Dear [recipient's name]:
Now that we have unpacked the boxes and hung up the pictures, it's time to welcome our colleagues and friends to our company's new location. Please join us for an open house on Friday, October 14, from 5:30 to 7:30 p.m. at 123 Allen Street. We will be offering beverages and light snacks, as well as tours of our offices.
Please RSVP via e-mail to Kim at [kim@XXXXXXX.com] by October 7 to let us know whether you can attend.
Hope to see you at this special celebration. We owe our success to colleagues like you, so please accept our sincere gratitude for your support.
[Sender's first and last names]