Is it possible to have a short cut to change stem direction ?

I'm new to Notion 6. Whilst writing my piano score I have often found that inputting a melody, for example a G on the top treble clef line, defaults to a downward stem in voice 1. Could there be a short cut to very quickly Esc from editing and use a shortcut to reverse the direction of the stem and keep it this direction until requested otherwise ?

Colin.