Show publication date instead of creation date

Hi,

I was wondering how I can show the publication date on the frontend of a blog. My client writes sometimes some blogs ahead, and sets a publication date when the blog post should become visible on the frontend. But the posts are dated with the creation date, and not the publication date. Can't find anythiing to change that, did I overlook something? Because I can imagine this will be a feature that is needed by more people than just my client

Thanks a lot.