Switcheroo:

Switcheroo is like replace, except instead of replacing "Text A" with "Text B",
it replaces every instance of "Text A" with "Text B",
and every instance of "Text B" with "Text A".
So using Switcheroo and selecting
Switch: Dog
With:     Cat
on the following text:
"The Dog chased the Cat, and the Cat bit back."

Will yield:
"The Cat chased the Dog, and the Dog bit back."