If you mean in a drawing, use the Model in view to which the annotation is attached option.
If you mean in a model sketch, use the Current Document option.
If you mean in Edit Part > Edit Sketch mode while in an assy, I don't think you can.
If none of the above, please clarify.
If you mean in Edit Part > Edit Sketch mode
I mean when I am editing a sketch in a part that is contained in an assembly.