Change of major WITHIN Bio dept ?

Hi, son is admitted as freshman into Human Biology major in the Bio dept.
He prefers the Neuroscience and Physiology major within that same dept.

UCSD site on capped majors say transferring within a dept is not an issue.
So should he apply for a change right away? Or best to do it later after he’s started his courses ?
Advice welcome.

thx
-john

He can do it whenever. All the bio majors have the same lower division courses but different upper divisions depending on what their specialization is in.