Switching instruments after you've started

I've setup a score and wrote some music but now I think I want to change the instrument.
Is there an easy way to do this? I've looked through the docs and this forum and couldn't
find any mention of it. I suppose I could create the new instrument then copy and paste what
I've written so far - I'm just looking to see if there's an easy way to swap them before I do that.
Thanks
Is there an easy way to do this? I've looked through the docs and this forum and couldn't
find any mention of it. I suppose I could create the new instrument then copy and paste what
I've written so far - I'm just looking to see if there's an easy way to swap them before I do that.
Thanks