Follow instructions 1-5 for Registering on the Web.  On the Add/Drop Classes page, click on the arrow under Action next to the course you wish to drop.  (The word NONE will be next to the arrow.)  Click on Drop Web.  Do this for each course you wish to drop.  If you wish to add a class to replace the class, type in the five digit Course Reference Number (CRN) of the course you wish to add in one of the boxes at the bottom of the screen and click on Submit Changes.  Scroll down and check for error messages.  If you have selected and/or dropped courses and have no error messages, click on Complete your Registration at the bottom of the page.