Display Screen or Portion Thereof with Transitional Graphical User Interface

FIG. 1 is a front view of a first image in a sequence according to a first embodiment of our design for a display screen or portion thereof with transitional graphical user interface;

FIG. 2 is a front view of a second image in the sequence thereof;

FIG. 3 is a front view of a third image in the sequence thereof;

FIG. 4 is a front view of a first image in a sequence according to a second embodiment of our design for a display screen or portion thereof with transitional graphical user interface;

FIG. 5 is a front view of a second image in the sequence thereof;

FIG. 6 is a front view of a first image in a sequence according to a third embodiment of our design for a display screen or portion thereof with transitional graphical user interface;

FIG. 7 is a front view of a second image in the sequence thereof;

FIG. 8 is a front view of a first image in a sequence according to a fourth embodiment of our design for a display screen or portion thereof with transitional graphical user interface; and,

FIG. 9 is a front view of a second image in the sequence thereof.

The appearance of the transitional image transitions between the images shown in FIGS. 1 through 3 , between the images shown in FIGS. 4 and 5 , between the images shown in FIGS. 6 and 7 , and between the images shown in FIGS. 8 and 9 , respectively. The process or period in which one image transitions to another forms no part of the claimed design.