CORTINA D’AMPEZZO, Italy — Sitting in the middle of the Cortina course following her second fall in four days at the resort where she once dominated, Lindsey Vonn slammed the snow angrily with her right pole. Then she got up and skied down to the finish — fortunate to have come away mostly unscathed again — and ready to assess the most difficult weekend of her comeback at age 40 with a new titanium knee following nearly six years of retirement. “It’s just going to take a little bit more time,” Vonn said, “I need to be patient myself and I hope that everyone can be patient with me so that I can just keep my expectations in check and and just keep trying to get better every weekend.” Vonn told The Associated Press on Thursday that she plans to retire again after next year’s Olympics, when women’s skiing will be held in Cortina. “I need more training, I need more time.