subplot(m,n,p)
should set the next plotting axes to the one in position p of your (m,n) grid in the same way as it would have done when you first plotted it.
To keep everything except the data the same you can simply use
set( hPlot, 'XData', newXData )
set( hPlot, 'YData', newYData )
if you get hold of (or already stored) the handle of your current plot on those axes. I think one of your previous questions received an answer that shows you how to get the handle for your line that would go where hPlot is above.
If you simply replot the data I think you will need to replace the title and labels also
