How to do this: (You need a DEing friend to help out)
1. Do an instance with them, when an item drops, have your friend greed for DE and you don't roll on the item (wait for it to pass automatically). Then just whisper your friend saying "damn I wanted to need that item but the loot window never popped up" (for more credibility).
2. Have the friend give you the shard/void (so that you can "trade it in" with the help of a GM for the epic item).
3. Have your friend open a ticket saying how he got the item and DE'd it but that you were supposed to need on the item.
4. You will receive the item in your mailbox and you will keep the void/shard (they can't remove it from you since it was your friend that DE'd the item, not you).
Now you might think this takes too much time, but it really doesn't. Say you're doing HMgT, it takes: 10 sec to whisper your friend, 30 sec for your friend to loot the item, DE it and give it to you, and 20 sec for your friend to make a GM ticket. It only takes 1 minute.
Of course, this was tested and verified by me (I discovered this exploit accidentally when I couldn't roll on an epic off HMgT).
Edit: When I did this it wasn't "tricking" a GM, it was an honest ticket and I discovered that you keep the shard/void. I have a picture of me taking the blade off the mailbox and having the void crystal in my bag and I know it could be easily faked, but here it is:
It does not use an item restoration, it's classified as an item transfer. And as for the GM tickets taking a while to be answered, I know, but you don't even have to be online and this will work just the same.