Angelina was used to coming to the door out of respect. After the war she was twitchy about letting anyone apparate or Floo directly in to her home. She came to the door because she wanted the warning of a knock on the door when someone entered her home.
"Thanks, I almost added red wine to the mess," she said. Her large purse (which had a change of clothes tucked in it) had slipped off her shoulder and was weighing on the arm holding the wine when Katie answered the door.