There are many salesman, vendors, implementors, programmers, designers, developers, and handymen who call themselves consultants. Many are not. A consultant uses their experience and expertise to improve their client, not to sell a product or service.
Many companies determine a course of action and hire someone to follow through. An implementor will do just that. A consultant will question why, and be sure that the client truly needs the intervention they’ve sought out. The difference between the client’s perceived need and their actual need is value provided by a consultant. The difference between the requested outcome and the necessary outcome may be even greater, and also represents value provided by a consultant.
Below is a visual I use to explain this relationship.