This song encourages the happy release of things that helped you in the past, but that might now be holding you back. It's like a mini ritual, and can be sung when you know you are ready to let something go and just need to appreciate it one last time, and acknowledge that you are a different person now.
 
The words to the second line apply to lots of experiences but can be changed to reflect anything the singers are ready to release.
 
Thank you for
The courage to get this far
And now I've grown
And I let go