It is called a “letter of intent”. I have done LOTS of them in my work as a broker and when I did leasing for a national retailer.
If this is a professional landlord, you can start with his LOI and go from there, but I would suggest that you get yourself a tenant rep broker to work on your behalf.
If you want, PM me your phone number and I will call you and talk you through it a bit. If you are in a market where I know a broker (most major cities) I will refer you to someone good.
