Registered Patent Agent

Always use a registered patent agent

The keyword is registered You can easily verify the registration of a patent agent at the website of the Patent Office where the patent agent is registered, e.g. the Canadian registration of Peter Kwa is here

There is a first reason for using a registered patent agent, and a second (different) reason for avoiding the use of non-registered individuals. The first reason has to do with the complexity of patent law and practice, and all Patent Offices around the world strongly recommend the use of a registered patent agent to help you with patent related matters.

Although you would not go to a non-registered "doctor" either, here is how Wikipedia explains the second reason for avoiding the use of non-registered individuals.