Legal Question in Business Law in Maryland

Re: Formal resignation

If you want him out of the company, which I presume from the way you worded the question, you could argue that personally delivering the resignation letter is the functional equivalent of sending it by certified mail. The purpose of requiring certification is to verify delivery to the recipient, which is accomplished by personal delivery as well. If your friend has conducted himself as if he's out of the business since handing over the letter, that strengthens your position.