Respuesta :
The focus change is in the point of view; first, she thought that she did her first sale and was ready to do it, as nobody opened, she thought there was nobody at home. Then, she changed her point of view because she thought to return and that she wasn't a good salesperson, however, she knocked on the door again with a smile on her face.
The primary change is a change of place.
Suszanne is giving her first try as a saleswoman: "She was ready to make her first sale." This first try is in a house; the house is empty: ' "I guess no one is at home," ' she said and turned to leave.' Then, she gives it a try in another house: " she thought as she walked hesitantly up the steps to the green house next door."