How am I supposed to move only Gizmo when in Edit mode? Yes.. I know cursor to origin funtion with 3D cursor. 

but i can't find way to only changing pivot in Edit mode.

I want move Only Gizmo in edit mode... like zbrush transform tool.

There is no snap menu in right click.

Is this situation need 3D cursor use?

Do you have Any other Idea?
Exactly... You can easily solve this using the 3d cursor...

First be sure that you set the pivot point to the 3d cursor (in object mode): 



Back in edit mode you select the edge where you want the center of rotation and hit Shift+S to set the 3d cursor to that edge: 



Problem solved, if your cursor is at the right place you can rotate everything around that point: