My answer before works in NX 11. In NX 10 use the edge to face option. Select the edge between the face and then select the blend face near the same edge. Then follow the directions as I pointed out before.
A real quick way is to use the tangent face selection rules. Start a command that requires face selection (Synchronous Move Face for example). Set the Face rule to 'Tangent Faces' and then select one face. All tangential faces will be selected.
"btw, can we use reflection tool also?"
If your only requirement is that the surfaces are tangent, then the reflection analysis isn't the best tool for the job. It works best when you are looking for ripples within a surface or curvature continuity between surfaces. Surfaces may be tangent, but not curvature continuous; a "rolling ball" type blend (the standard option for the "edge blend" command) will be tangent, but not curvature continuous. In a reflection analysis, if the surfaces are tangent but not curvature continuous, the flow lines will meet at the interface, but may veer off at a sharp angle. Surfaces that are curvature continous will have smooth flow lines across the interface.