How do I apply a template to an existing document?

[SixSigmaGuy]

Our company's standard Word Document template recently changed (fonts
changed, logos were replaced with new logos, etc.). I have a lot of
exisiting Word Docs that I have to switch to the new template. The new
template has footers and headers. How can I apply the new template to my
existing documents? I can get the fonts to update to the new format, but the
logos, footers, and headers, don't.

Can someone tell me if there's a way to apply templates to existing documents?

Thanks,

Rick