We investigate the pathway of thinning process for transient  nanowires (NWs) of Ag. The result is in good agreement with experimental observations. An unambiguous identification of the structure of a NW requires at least two views along different directions. In the cases where two views of different NW structures are practically the same for very thin NWs which pose experimental difficulty due to small signal-to-noise ratio, our theoretical analysis helps distinguish these structures. On the basis of conductance (G) calculations vis-á-vis the structure of transient NWs, the puzzling experimental observation of fractionally quantized G values is explained by considering the existence of mixed structures for thin wires.