What happens to Daisy's mother after visiting the opening of Selfridge Department Store? How is Daisy affected by this mentally? What changes occur in Daisy's lifestyle after the event?

Daisy's mother dies from a heart attack three days after she and Daisy attend the opening of Selfridge Department Store. Daisy is upset because she is at work when her mother dies. Upon her mother's death, the quarterly allowance left by Daisy's aunt stops. Daisy decides to move.