Is there a function that can stretch the place and route boundary box after it's been drawn or re-draw it ?
Thanks in advance,
Not sure why you need a function - you should just be able to stretch it in the layout editor as long as the P&R Boundary is selectable.
In VLS XL you can just do right mouse menu over the P&R Boundary and control its selectability. Other than that, go to the Objects assistant (part of the palette), and find the Boundaries and ensure that P&R Boundary is visible and selectable. Having done that you should be able to use the normal stretch command on it.