If you are thinking about changing your course, the best thing to do is to talk to the department directly to find out your options. There is no guarantee that you will be able to switch courses - it will depend if there is space on the new course and if you meet the entry requirements etc - but it is worth getting in touch with the department to find out their policy on changing courses. You can find contact details for the UCL Maths department on our website, and you might want to start by talking to the admissions tutor.
Before you commit to a swap, make sure that you research the content of the new course and check it is what you want to do. You can find details about all UCL courses in the prospective students area on our website.
You can also find out more information about switching courses at UCL here.
Hopefully this helps!