How do I get my mom to let me hang out with friends that she does not know?

My mom wont let me hang out with my bestfriend bre and she says its just because she does not know her But ive known her for along time and my mom wont let me stay out late! ugh They will be gone a week after christmas i will be with my grandmother umm and me and bre wanna hang out so please tell me HOW TO CONVICE MY GRANNY TO LET ME HANG WITH FRIEDS MY MOM AND DAD!