Display screen or portion thereof with transitional graphical user interface

FIG. 1 is a front view of the first image in a sequence for a display screen or portion thereof with transitional graphical user interface, showing my new design;

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

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

FIG. 4 is a front view of the fourth image thereof;

FIG. 5 is a front view of the fifth image thereof;

FIG. 6 is an enlarged front view of the portion enclosed by the dot-dashed broken lines in FIG. 1 ;

FIG. 7 is an enlarged front view of the portion enclosed by the dot-dashed broken lines in FIG. 2 ;

FIG. 8 is an enlarged front view of the portion enclosed by the dot-dashed broken lines in FIG. 3 ;

FIG. 9 is an enlarged front view of the portion enclosed by the dot-dashed broken lines in FIG. 4 ; and,

FIG. 10 is an enlarged front view of the portion enclosed by the dot-dashed broken lines in FIG. 5 .

The appearance of the transitional graphical user interface sequentially transitions between the images shown in FIGS. 1-5 and FIGS. 6-10 , respectively. Variation in the dot density of stippling shown in the drawings illustrates contrasting appearance. The process or period in which one image transitions to another forms no part of the claimed design.

The outer perimeter illustrated by a pair of dashed broken lines in FIGS. 1-5 represents a display screen or portion thereof and forms no part of the claimed design. The remaining dashed broken lines shown in the drawings illustrate portions of the graphical user interface that form no part of the claimed design. The dot-dash broken lines define the boundary of the claimed design and, in FIGS. 6-10 , illustrate a portion of the display screen. The dot-dash lines form no part of the claimed design.