The flat fee for one Chicago change of contractor permit is currently $75. Note that if you are going to change multiple contractors under the same application, the fee will still be $75. As an example, let’s say that your current plumbing contractor is unable to complete work on the project for one reason or another. In order to get a new plumber to work on the project, you will have to apply for and pay for a change of contractor permit. That will cost $75. Let’s say that you need to change the roofing contract a month later. In this case, you will have to apply for another change of contractor permit that will cost an additional $75.