Two methods are available for redefining the boundary of a layout viewport.
Adjust a layout viewport boundary using grips
Click a layout tab.
Select a layout viewport.
Click one of the rectangular size grips on the layout viewport border, and adjust its location.
Redefine a layout viewport boundary
Click a layout tab.
Click
Layout tabLayout Viewports panelClip.
Find
Select either an existing object to designate as the new viewport boundary, or specify the points of a new boundary.
The new viewport boundary does not clip the old boundary, it redefines it.
Click OK.
On the layout, specify two points to indicate the area to contain the viewport configuration.
Note: A nonrectangular viewport consists of two objects: the viewport itself and the clipping boundary. You can make changes to the viewport, the clipping boundary, or both.