Most students taking 3rd year courses likely already know well how to transfer between sections… but just in case…

The Undergraduate Enrolment and Registration Guide contains the instructions:

If enrolled in a course with multiple lab meeting groups, tutorial meeting groups or course sections, you can transfer to a different lab, tutorial or section of that same course in the same term:

1. Click Transfer a Course.
2. Type the catalogue number that you want to transfer into.
3. Click Transfer Course. The catalogue number, course and title will be displayed. If this is the transfer you want, then click Yes.

A course transfer can be made without financial impact.

If the target section is full, then you will not be able to execute the transfer.