im drawing a line from 0,0 to 100,100
im using this to modify the linestyle:
draw_line.graphics.lineStyle(1, 0xFF0000);
That line is now of 1 thickness.
Is there anyway i can change the thickness of the line to say 10, but without redrawing the line?
No, it is not possible with the way the flash player works, you must redraw the line. Or use some kind of library that automatically redraws it for you (for example a Line object in the Flex 4 Framework)