This is relatively specific question: say the KKE contests the Greek elections in 1946 on orders from Moscow to play nice - IOTL Stalin couldn't give a toss, partly due to the percentage agreements and let them wallow.
As a leader of the National Liberation Front they have plenty of credibility and I think, judging by rough figures of abstaining voters, they could have pulled a very large chunk of the vote particularly if they emulated their French comrades and played their patriotic, freedom fighter card.
On issues of land reform, the monarchy and dealing with collaborators, they were in agreement with much of the centre and centre-left. Also powerful moderates like Soufolis were for coalition on these issues. So say a Popular Front government is formed. Crucially there is no immideate civil war.
However my question is: how does it play out? Greece is in unique position - there's no Soviet troops on the ground, the partisans effectively liberated the country, though the German pull out didn't hurt, and there is a small British contingent trying to keep the peace.
Would the Communists try to stay parliamentary? Given the inevitable crack downs elsewhere it would seem they would be doomed to later electoral defeat. Also the KKE, unlike their French counterparts would probably be the single biggest party, so would have a few cabinet posts. Do they try to encroach on power like the Czechs? If they dominate, whats to stop them legally kicking the Brits out and asking the Soviets to come in?
Do we see a coup? If so, the USSR can cry wolf if the British don't intervene.