How do I change "forgotten root password" in RHEL6.5 Guest server?

I have forgotten the root password in my guest server running RHEL 6.5. I could change from 'booting through single user mode'. But it comes up with "Maintenance Mode" which is asking for root password (or CTRL+D to get out and boot as is). I cannot update the system or start any stopped services anymore. Any one can help me? It will really help me. NazHusain.