It is not uncommon for students to change courses once they are abroad. This may be because of courses being closed or canceled, because a student is at a different language proficiency level than the course that s/he registered for, because of a scheduling conflict or because the student wishes to take a different course that looks attractive.
While this is possible, students are required to contact their adviser and get written approval for the changes. This approval must be sent to the OIE for incorporation in the student's folder. Failure to get such approval could lead to a delay in graduation and failure to get the course equivalencies that the student seeks.