To turn the tide, blaze a new trail, or otherwise go against a pre-established or preconcieved rule, idea, norm, or expectancy.
Lupe Fiasco would flip the script of the rap game when he released an album that didn't rely on cliched rap tenets such as drugs, sex, and violence to be commercially successful.
Any situation where one or more parties has spontaniously changed their mind or manner, deviating from an understood "persona" or public image or personality. Essencially being hypocritical, two-faced, or sanctimonious.
"She loved me yesterday but today she hats me......Why does she always flip the script on me???"
"You should work 1-2 days a week, thats fine its your schedual, thats a perk of this job."
Then saying.......
"You are only ever on 3 days a week, you have to book on five days a week. Your like never here."
When someone does something deceitful to you, you forgive them, and they take your kindness as a weakness and think they have the upper hand. Now you turn around and do the exact same thing to them, but they never see it coming because they thought you were weak! Gotcha.
Mike made plans with me, later confirmed the plans, seemed really excited about everything and called two hours before to cancel, turns out he had no means to keep the date from the start. I laughed it off, accepted another date and flip the script, this time I no-showed for the date.