You will be better off WITH THE ENGINE COLD to just remove the hose and replace it, wont loose that much coolant. Some times the plastic drain cock can break in the radiator! Just put down some old rags under van befor starting work. When finished, bag up soaked rags and despose of properly.
Keep pets away from coolant!! Remember COLD engine!! Loosen rad. cap then tighten it back before work, will loose a little bit less coolant that way. Refill radiator when finished working.