You randomly bump into her somewhere... Also, make sure you have changed something about your appearance that she will instantly notice.
You can not be the same "you" that you are now.
This ^^^^ basically but I would do it in 2 parts, seems like you will try so might as well try and help you, lol,... Part 1, yes stand out some how, go on a diet, jump on some tren, lol,.. OK enough joke in all seriousness when you come in contact with her, make it only a split second, act like you are in a hurry, don't stop to talk, simply walk by and say "hey what's up, nice seeing you, got to run talk to you later",... and split quickly, she has to be convinced you have lost interest in her, this is the only way, trust me. Part two, another few weeks minimum, then when you see her stop and talk, this time she won't be expecting this based on your last reaction, which makes you unpredictable, hence she might be excited again. This is your only shot and it's a stretch already. Remember the longer away the better in every case, period.