Only if you are a paid customer. The free service does not allow this, and this is why I do not use Cloudflare for personal use.
I'm running the web servers, official wiki, and game external resource portal for the most active open source video game on github, through cloudflare, and maybe we might not want our 60 million requests a month website to go down when cloudflare does.
Because I can tell you right now our 300 a month budget (that mind you, is capable of covering 7 game servers that can handle 100 connected players (each)) can't take the 80 dollar hit just to make cloudflare not a single point of failure.