You should be worked with your company at least 1 year and of course you need that NOC.
Also it depends if they cancelled your RP, you need to go back in your home country and wait for their new company visa.Because once ur RP CANCELLED you need to exit in qatar.
Other alternatives, you have to renew again your RP so that you dont need to go back in your country.
This is better way of changing sponsor and additional requirements you need a police clearance, computer number of your old company and lastly with your original NOC with stamp.....
merry xmas