In the first instance go to office's, ask at reception for a complement slip and the name of the facilities manager, then walk away.
then you can either phone or write a letterfor eg...
Dear (you will have the name)
May I introduce myself and my company to you.
the purpose of this letter is to inform you that we have one or two new developments within our service range that may be of interst to you.
I obviously have no idea at this stage if this is the case, so I will be telephoning you within the next 7 days to see if we may be able to fix up a very short meeting where I can explain in more detail our latest service range
I look forward to speaking to you.
Yours sincerely
Your Name
You can find all this and morein a book called selling to win by Richard Denny
I have found this book to be profitable.
Dennis