There is no undelete or undo in TurboTax Online. All changes are saved immediately and permanently. As soon as you delete something it is gone for good. You will have to reenter the W-2 when you get the W-2 form from your employer. They have until January 31 to put it in the mail.

If you haven't done too much entering yet you could try to clear and start over.  Then it should retransfer it from 2015.
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