Dear Sirs,
This is to bring to your kind notice that our business, during the last two years, has expanded considerably, thus, making it necessary for us to shift our office to more spacious premises.
We would like to inform you that we are, therefore, shifting to a new and much spacious office premises and shall start functioning the new premises with effect from date _____.
Our new Address is
______________
______________
______________
Thanking you
Yours faithfully
Name