Each free ticket code is only valid for one free ticket. So as long as you haven't used the code yet, you can certainly share that with a friend or family member.
The codes are unique and will only work with certain ticket vendors that are our partners. So you'll want to share the link to the ticket vendor included in the email where you received your code.
For more detailed instructions on redeeming a free code, visit this blog post: Redeeming a Free Code