HI…I have an existing trading account (in HUF name) with Zerodha and now would like to open a demat account(in same HUF name)…
what would be the procedure? Can it be done online?
You already have a trading account (without Demat account), and want to open Demat account, right? The process is not online, you will have to download, print and fill the form and submit it to Zerodha HO, you can read this for more.
OK,just went through the form
1/.Does KYC form need to be filled and sent again i had filled same form for trading account?
pages 3 and 4
2/.Does POA need to be filled since now it is a new system?
last 3 pages
3.If i have a demat account with another broker can i shift it to zerodha?
CDSL TPIN facility is not yet available for HUF accounts, so you will have to submit POA.
You cannot map a third party Demat account to your trading account, once you have opened Demat account with Zerodha, you can transfer your holdings.
Not so sure about this 
would suggest you raise a ticket from here, team will get in touch with you.
If an individual is presently overseas is it possible to open an account in Zerodha?