Life Swap

No one takes the Dream Stone seriously. It has been sitting in the Victoria and Albert Museum in London for 150 years, but the legend of the Stone granting wishes to the righteous has become a bit of a joke. But Kelly Hughes is on a school trip, and she has to complete her worksheet to avoid a detention, so she goes to see the thing. And she meets Olivia Montague in front of it, a little kid from another school, who she accidentally bumps into. Then, caught up in a freak accident, Kelly is thrown against the Dream Stone and knocked out, and when she wakes up, she watches herself walking away from the scene. That is when she first realises that she is trapped in Olivia's body.
I first tried out this idea in The Dream Stone, which is still available on Wattpad, but this is not the same story. It is deeper, longer and takes the basic premise further.