Switch off compressor, depressurize, extract refrigerant and oil

The compressor is under pressure!

Serious injuries are possible.

Depressurise the compressor!

Wear safety goggles!

Switch off the compressor which is being worked on, or the entire system, if necessary, and secure from being switched on again!
Let the compressor cool down.
Close valves (suction gas side, discharge gas side, Economiser, refrigerant injection, oil supply).
Depressurize compressor.
Extract and reuse refrigerant.
Drain oil, store sealed and dispose properly!