Hey There, Hi There, Ho, There, Jenna! 
You're as welcome as can be, here at planDisney! Thank you for bringing your question our way, and I'm sorry you've been having a little trouble linking your 
MagicBands to the correct Guest. It looks like you're right in the heart of the Most Magical Place on Earth, so let's not waste another minute! I wouldn't want you to be late for a very important date...at Walt Disney World! Let's dive in and get this sorted out!
Usually, once a MagicBand is linked to a Guest, it can't be reassigned or transferred to someone else. However, since this was an accidental link and your MagicBand hasn't been used yet, there's still a possibility of getting it taken care of.
The easiest way to do this is by reaching out to the Cast Members by using the chat feature either on the Walt Disney World website or directly within the 
My Disney Experience app on your phone. They're super helpful and (fingers crossed) can assist you in making sure your MagicBand gets reassigned correctly.  
If you prefer speaking with someone directly, you can also call the 
App and MagicBand Support line. These Cast Members are the experts at this kind of thing, and they'll help to ensure each band ends up with the right Guest.
And if you happen to be in the theme parks, you can also stop by any 
Guest Relations location, where a Cast Member will be happy to assist you right on the spot!
Once this is all sorted out, take a deep breath and treat yourself to a DOLE Whip...you deserve it!
Jenna, I hope this helps, and you have the most MAGICAL vacation! Thanks for stopping by planDisney!
Pixie-Dusted Wishes,
Kami