Before you add or drop courses, please contact your academic advisor. The change may be simple and straightforward. However, your advisor can let you know if there are details or implications you were not aware of.
How you change your schedule will depend on whether MyUI is open for registration changes or not.
You can usually make schedule changes on MyUI before the 6th day of the fall or spring semester (1st day of summer term). However, you should check the academic calendar to make sure, and contact your advisor with questions.