In fact, run far, far away from this "professional!"
Whether he or she is just ignorant or a blatant liar, the designer is putting your business in jeopardy of being sued by the original copyright owner.
From the US Copyright Office website:
How much of someone else's work can I use without getting permission?
Under the fair use doctrine of the U.S. copyright statute, it is permissible to use limited portions of a work including quotes, for purposes such as commentary, criticism, news reporting, and scholarly reports. There are no legal rules permitting the use of a specific number of words, a certain number of musical notes, or percentage of a work. Whether a particular use qualifies as fair use depends on all the circumstances. See FL 102, Fair Use, and Circular 21, Reproductions of Copyrighted Works by Educators and Librarians.
How much do I have to change in order to claim copyright in someone else's work?
Only the owner of copyright in a work has the right to prepare, or to authorize someone else to create, a new version of that work. Accordingly, you cannot claim copyright to another's work, no matter how much you change it, unless you have the owner's consent. See Circular 14, Copyright Registration for Derivative Works.
You cannot take someone else's work, change part of it, and claim it as your own.
What does this mean for your business if you really want something kinda sorta like it was inspired by and captures the feeling of your favorite photo, painting, or song? By hiring a design consultant that knows and follows the law, you can have your art and keep your business too!
Here's a real case example of how to be inspired by, but not rip off, a logo.
The cousin of a graphic designer I worked with wanted a Native American company logo inspired by the Orange County Choppers logo.
As you can see, I could change ten percent (one square), twenty percent (two squares), or even thirty percent (three squares), and the integrity of the original design is still maintained. 
If you hired someone to take an existing logo, "make a couple of changes," and then try to claim it as your own, you and the designer would be guilty of copyright infringement.The graphic designer never came up with the requested design (she didn't feel "inspired" or whatever), but the idea stuck in my head.
Zoom forward four years to the recent Christmas holidays. I had some free time, so grabbed a paper and pen and looked at the OCC logo. I noticed the flowing, abstracted style and how the initials are incorporated into the chopper. I decided to use a flowing, very abstracted style for my image, but did not use any letters. I also looked at photos of choppers. I didn't trace or copy/paste anything from the images I was using as reference material.
I wanted to have a rider in my image, one that could indicate a Native American. I thought about the beautiful flowing straight black hair of many Native American people, and decided to use that in the design.
What I created could have several meanings - I see a motorcyclist, a chopper rider, a Native American, a recumbent bicycle rider, and a bicyclist wearing a racing helmet.
What do you see?
For more information about US copyright law, visit Step Inside Design magazine and copyright pages on About.com
