Hundered Acre Mix-Up

Pooh and the gang literally end up changing their personalities to stop Rabbit from moving away; Eeyore becomes a jolly honey-eating donkey like Pooh, Piglet becomes a bouncy cloudcuckoolander like Tigger, Tigger becomes a scaredy cat like Piglet, and Pooh becomes a perpetually sad and gloomy slump like Eeyore.

Example of:
Role Swap Plot