Calling two functions to a diff m.file

Don't know if am asking this question in the right way but i have two reverse audio button for two different plot but i want to call them both into one plot in another window/m.file. 'global y;' is for the first reverse button and 'global y2;' is the second.

   global y;
  %global y2;
  global Fs;
  global reverse_b;

reverse_b = flipud(y);
plot(handles.axesMix1,reverse_b);
reverse_b = audioplayer(y, Fs);