How to get out of Endless

Hi,

Common story, new laptop, boots to Endless. I don’t want it to boot to Endless, I want to install W10. It doesn’t boot off my W10 drive - which it should but hey, we’ll get there. I can’t get away from endless to debug what’s going on though. How can I /not/ boot with endless; delete endless; get to a command prompt from endless or /anything/ other than endless?

Thanks!

Evan