Display Screen or Portion Thereof with Transitional Graphical User Interface

FIG. 1 is a first image of the display screen or portion thereof with transitional graphical user interface in accordance with the present invention;

FIG. 2 is a second image of the display screen or portion thereof with transitional graphical user in accordance with the present invention; and,

FIG. 3 is a third image of the display screen or portion thereof with transitional graphical user interface in accordance with the present invention.

The broken lines illustrate environmental structure that form no part of the claimed design. The broken lines illustrate the display screen or portion thereof that form no part of the claimed design. The remainder of broken lines illustrate portions of the graphical user interface that form no part of the claimed design.

The appearance of the display screen or portion thereof with transitional graphical user interface sequentially transitions between the images shown in FIGS. 1 to 3 . The process or period in which one image transitions to another forms no part of the claimed design.