My first application was made by an attorney the second one I did it myself.
But before your sister applies again make sure you have all the right paperwork otherwise she may get denied again.
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Sent: 12/26/2014----Received: 12/29/2014
Receipts: 01/07/2015---- Biometrics: 02/06/15
Received RFE Notice: 06/11/15-- USCIS Received RFE: 06/15/15
APPROVED: 06/19/15