Cooling systems without a drain valve

What are the methods used to replace coolant on a vehicle without a drain?
I am due to change the coolant on a vehicle with a very tight engine bay and no drain plug in the radiator. The hose clamps are almost impossible to reach because it’s a turbo engine and the front mounted intercooler pipes are in the way.
On vehicles with a drain valve in the radiator, it’s a very controlled process, coolant is emptied into a bucket or pan with minimal effort and mess, what methods can be used in systems without a drain?
There is no radiator cap either, just a Schrader valve for bleeding air and a coolant reservoir away from the radiator.