This is the scenario of the screwball revenge comedy You Again, directed by Andy Fickman. The story lives up to the cliche of the title: it's about women at war over past humiliations.
A successful public relations employee Marni (Kristen Bell) learns her older brother Will (James Wolk) is to marry her high-school nemesis, Joanna (Odette Yustman). Joanna was the bully who made Marni's nerdy, high-school life miserable.
Marni decides to reveal Joanna's true character and "rescue" her brother by sabotaging the wedding. We also discover Marni's mother, Gail (Jamie Lee Curtis), had problems with a high school rival, Joanna's Aunt Ramona (Sigourney Weaver).
This is a Walt Disney comedy, so you can probably guess what happens next: a series of entertaining but silly scenes including fights at a pool and dance. At the end, those looking for revenge will regret what they did ... and everyone will learn to forgive and become friends.
If you're looking for something light-hearted, with a few good laughs, this might suit you. The sight of Gail performing a cheerleader dance, and the denture gags by Marni's Grandma Bunny (Betty White) will certainly not disappoint.