Yes!
You can copy your project. Then open the copied project and you can change the audio file or edit any other aspect of it just like any other project.
Click here to find out how to copy your project!
Another option- use an intro or outro video. Headliner allows you to upload a MP4 to the beginning or end (or both) of your project.
Click here to learn how to add an intro or outro to your Headliner project.