JX2020

I am an undergrad studying CS in a Canadian university and I am applying to some PhD programs in the US. In some schools (e.g., Stanford), PhD applicants are not required to submit a GRE score but masters applicants are. I did not take GRE, so I do not have a score. I heard it is common that people apply to the PhD program but get offered to the masters program instead. If I do not have a GRE score, is that not a possibility for me? Thanks!