§1. Without prejudice to the prescripts of can. 647, §3 and can. 648, §2, an absence from the novitiate house which lasts more than three months, either continuous or interrupted, renders the novitiate invalid. An absence which lasts more than fifteen days must be made up.
§2. With the permission of the competent major superior, first profession can be anticipated, but not by more than fifteen days.
Source: Code of Canon Law (Vatican.va)