Once you decide on a major the next step is to actually declare that major officially. Be sure to consult your advisor before switching, since there are some majors which have additional or stricter requirements.
Once you know that you have satisfied all the requirements for transferring into your major of choice you must get a yellow Change of Major card. This can be picked up at 104 Sikes Hall or the Academic Advising Center.
Fill the card out and then go to the department chair or academic advisor of the major you are going into, your new major. Then come to 201 Strode Tower, the Advising Center and your Undeclared advisor will also sign the card.
The entire card must then be returned to 104 Sikes Hall where it will be processed and your major will be officially changed.