The process to declare your major (or minor) is online in myBanner.
Log into myBanner using your G# and Pin#
Click on Student
Click on Student Records
Click on Change Major at the bottom of the list of menu items (even to change your minor)
Click on the item you would like to update (major 1, major 2, minor 1, etc.)
Select the appropriate program from the drop down list (choose degree and emphasis if appropriate)
Click on Submit
Click on Change to New Program
You should return to the main student menu and see a message that says the changes have been successfully submitted. You will then receive an email within a couple of business days confirming the change and providing you with information from the department.