Mrs. Lancaster is the owner of the B&B where Phil Connors keeps waking up over and over. She is a well-meaning nice lady who doesn't seem to understand Phil's sarcasm. She also isn't the most educated person: when Phil asks her,
PHIL: Do you ever have déja vu?
MRS LANCASTER: I don't think so, but I could check with the kitchen.
Mrs. Lancaster is a nice person, and it's not until Phil learns to be kind to people that he can change his behavior toward her and treat her the way she deserves.