This is a confusing thread. To me the word "convert" implies that the miles were already posted to an Eastern Miles account and you want to move them to Skymiles (you can't do that). But subsequent posts imply that's not what you mean. My undestanding is this: you've already flown the trip; the miles haven't posted to Skymiles; you don't have an Eastern Miles account but are considering opening one to post the miles because you don't like that Delta only give 50% credit for a T fare.

If you provided your Skymiles number on the reservation, then the miles should post automatically to your Skymiles account after a few days. Check your China Eastern boarding passes to see if your Skymiles number is on them. If it is, wait a few days and the flights may automatically post to your Skymiles account anyway. If they don't then file a retro-credit claim. IMO, there's no point in opening an Eastern Miles account if you rarely fly on them and already have status and miles accumulated on Delta. The miles/MQMs might only be worth 50% on Delta, but they only earn 50% on Eastern Miles too. And they will be pretty much worthless to you in a Eastern Miles account.