As Patty indicated, you (as a Vice President and Officer of the Company) are still an employee of the company. You leave that position by submitting a letter of resignation to your boss. As a former officer of the company, you may bear some legal responsibilities to individuals for fradulant activitiy that took place while you were an officer. They would have to prove a number of things that could be difficult to prove, but if you are named personally in a suit, get an attorney.

Since you and your "partner" formed the corporation, I assume that there is stock and that you own some of the stock; and also that incorporation papers were filed with the state showing you as an officer, a major stockholder or both. To completely wash your hands of the situation, you should return your stock to the corporation and file papers with the state to reverse your filed relationship with the corporation. Normally, this is something that a corporation would do when removing a named officer. But, assuming that your partner may not be willing to do it, you should probably do it yourself.