How can I purge radiator in a chevy venture 2003?

I have been looking for a valve at the bottom of the radiator but did not find it, I would like to change anti coolant liquid I will appreciate your help.How can I purge radiator in a chevy venture 2003?if there is no valve at the bottom of the radiator, then you can always remove the lower radiator hose. This can be a little messy, but works well. After the antifreeze is out, reinstall the hose. When filling with the new antifreeze mix, make sure to let the coolant system %26quot;burp%26quot; out any air bubbles. This is done by running with the cap off of the radiator, once the thermostat opens, you will see the fluid level drop a lot. Top it off, put on the cap, run for another five minutes, shut off vehicle, and check fluid level again once it has cooled off.