Per the premier league website.
Martin Atkinson has replaced Craig Pawson at Anfield tonight, Kevin Friend has replaced Atkinson as 4th official for the West Brom v Everton game.
That’s because they’ve messed up the appointments for the weekend
Craig Pawson stood down from refereeing LFC v Chelsea as a precaution after being informed that a close contact had tested positive for coronavirus. He will now isolate and has been replaced by Martin Atkinson this evening. (@dmlynch on Twitter)