NAME_1 wanted to go to a concert and asked her friend NAME_2 if she was also interested. NAME_2 said yes, so NAME_1 bought two tickets. One day before the concert NAME_1 called NAME_2 to remind her about the event, as it seemed to her that NAME_2 had forgotten about it. NAME_2 said that she had indeed forgotten about it and that she couldn't go due to other plans. NAME_1 was upset because she had similar experiences with NAME_2 before. What could NAME_1 do in the future to avoid similar situations while maintaining her friendship with NAME_2?