You need a new (or another) Google Account with an active Google+ Profile. But do not setup a G+ business Page there yet! You will transfer it together with your YouTube Channel to this new Google Account later.
• Then log into your old YouTube Account and link your Channel to a new Google+ business Page.
• Next add a new manager for that Goggle+ Page: Choose your newly created Google+ Profile (from above) as a manager.
• You have to wait 14 days
• and then you can transfer ownership of your Channel to the new manager.
the following How-to Tutorials should be of additional help:
~ Transfer YouTube Channel ownership to another Google account
~ How to Transfer YouTube Channel to another Google Account in 4 steps