Wrong Address

A mysterious mail came to my home today. It just appear in front of my door. But when I checked it it was sent to the wrong address.
I decided to just open the package, and inside it was a necklace, a letter, and an ID card. The letter said,
"Thanks for your body Nia, it was a blast being you! I no longer need it, so you can have it back." it was definetly a strange letter. I was lso curious about the necklace so I put it on.
In an instance I felt the whole world shifted and I almost lost my balance, before everything went back to normal. I immediately noticed that I was naked, and when I checked to make sure my whole body has changed. I am now having a woman's body. Running to the mirror I saw the reflection as the same face as it is in the ID. Somehow, I have shifted into Nia.
I took the necklace off, and nothing happened. But when I put it back on, I was shifted back to my old body complete with my clothes. So i figured it out, this necklace allow me to switch to Nia's body whenever I want. So I put on the necklace one more time, having my body shifted to the feminine form. And I think I'll try living the life as Nia for now. If it doesn't work out, I can always change back to my old body.