accidentally changed URL under General Settings..now can't access dashboard

Hi I am a word press website designer and i Designed my clients website yesterday he asked me that i want my visitors to go to the demo.jbintc.com and his website is jbintc.com i change the URL under general setting thought it should have work but everything goes wrong i am so tense can please someone help me very fast please tell me how can i recover it the shortest way i dont want to lose all my work
PLEASE HELP