I want to point to sub domain to another server. How it can be done?

You can able to point the sub domain to different server using the below procedure.

[1] Access your control panel at https://www.yourdomain.com:8443 [ Example :https://www.servername:8443 ]
[2] Click on subscriptions
[3] Click on the subscription name
[4] Click on Websites and Domains
[5] Click on DNS settings
[6] You can able to find the record demo.democom. A [Serverip]
[7] In server ip you can mention the ip where you want to point your sub domain.