How do I create a potential without creating an account?

How do I create a potential without creating an account?

When one of my salespeople gives a demo to a new lead, I want that Lead to be converted to a Potential and a follow-up to be scheduled. However, when I hit "convert" to create a Potential out of that Lead, Zoho also creates an Account for that Potential. 

What am I doing wrong? 

I want my Accounts to only reflect those that have decided to join our service and become customers, not those that were just given a demo.