"Lassie, there's something very important I have to tell you," Kelly said in a more serious tone.
"I know, I know - don't call you a 'garbage sniffer'. I get it!" Lassie said.
"No, that's not what I was going say." Kelly took a deep breath in, preparing herself for Lassie's reaction. "I'm not Sophie. I'm Kelly."
Lassie stared at her. They stared at each other for about thirty seconds before Lassie spoke.
"Sophie, if this is one of your practical jokes, it's not funny."
"No, Lassie, I'm very serious! Sophie and I have swapped bodies!"
Lassie turned around and started walking away from Kelly.
"Please! You have to believe me!" Kelly pleaded.
Lassie finally looked back and saw Kelly's face. True, the whole story might seem a bit fishy, but 'Sophie' seems the most sincere she's ever been.