Many schools have an Academic Integrity office or officer. Usually you can talk over the problem, learn about your options, and decide to file a formal report or not.
If this situation relates to a for-credit class, I assume you will get a poor grade in the class as a result of not having done the assignment or as a result of asking to have your name removed from the assignment that your partners are submitting. If you are switching fields, maybe that doesn't matter to you.
Reporting academic dishonesty (as opposed to just getting yourself out of the situation) is the right choice, but I know from several personal experiences that it causes short-term stress that you may not want to endure. You probably will find that it's not just the perpetrators who get angry at you. Some people within the school organization may well be annoyed that you are reporting the incident. There will be stress, so if getting yourself out of it is as much as you can contemplate doing, at least do that. Not everybody is ready to be a hero all the time.
Over the years, both as a student and as an employee, I have witnessed academic misconduct. I have never regretted reporting, but I have sometimes decided that reporting wouldn't be worth the trouble it would cause for me. I have taken on a considerable amount of trouble related to reporting, so I don't feel that I have been "weak" on the occasions when I have decided not to. If you've never done it before, you might find it to be an eye-opening experience.