NervousChemBiologist

I am currently in a masters program in the US and have accepted to join the PhD program in the same department and in the same University. I am an international student and am considering to go back home during the break. But I heard that you cant return to the US more than month prior to the start date specified on the I-20. But I was planning on returning early to get a head start in my research. I want to know if I can return back early considering I will be in the same university and just getting a "change of level" in my I-20 or I will have to stay home for the break and return only one month prior to the start of the program?