How about the waiver in DOS

What is the "Statement Of Reason" when the waiver goes to the procession of DOS? All the documents are sent to the DOS for about 3-4 months. But when I search the case number on DOS website, it is "pending". I found the other case(somebody else's) has one more document than mine. It is "Statement Of Reason". What is that? It should be sent by me or by Embassy?
Thank you.