Honda Accord 2000...how do you drain petrol tank...

Vehicle manufactures have made it extremely difficult to remove fuel from tanks. There are several ways, all not too easy. Try pick up a connection the fuel supply line either under the car or in the engine compartment and see if you can pump the fuel out of there, If the fuel pump is in the tank and has an anti siphon valves in it, this will not work. The other method then is to remove the rubber connection that connects the tank to the filler pipe and push a pipe into the tank from there.