How to change a template that already have text on it.

[Feejo]

I have pages already that have text in it, but I want to change the template
of it.

 

[John Google]

I have pages already that have text in it, but I want to change the template
of it.

This has been asked many times (once by me!) but it can't be done out
of the box. I think someone was thinking of writing a powerttoy to do
it.