Obtain a Change of Major form from your advisor. If your advisor doesn't have a copy of the form, you can get one from either the Undergraduate Studies office or the Graduate Studies office.
Fill out the form with the relevant information. This will include your name, address, and Wilkes Identification Number (WIN#). You will then need to fill in the blank for your current major and the major you wish to switch to. You will also need to write in the semester and date you wish to make this switch official. The last piece of information you'll need is the name of your advisor.
Turn in the form to your advisor. There is information that he must fill out on the form. After he has completed his portion, he will submit your Change of Major form to the head of the department to be processed.