How Do I Resign from an S Corporation?

If you intend to resign, you’ll first want to speak with the bank to find out whether they will release you from your personal guaranty. Just resigning from the corporation does not automatically release you from your obligations under the loan. If the bank won’t release you from your guaranty, even if you resign, you may want to think twice about resigning. Otherwise, you’ll have no ability to oversee the corporation and how it is spending or repaying the money it borrowed.
I've heard many stories of business owners who have resigned and the remaining business owners run the company into the ground, leaving the resigning partner on the hook for the major loans.
If you don't have a written shareholders' agreement, you may be at an added disadvantage if you need to collect from your co-owners. Both the guaranty and resigning from the corporation can have serious legal repercussions if not documented carefully, so be sure to hire a business attorney to help you through this process.