Display screen or portion thereof with transitional graphical user interface

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

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

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

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

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

FIG. 6 is a front perspective view of the sixth image thereof;

FIG. 7 is a front perspective view of the seventh image thereof;

FIG. 8 is a front view of the first image in a sequence shown in FIG. 1 ;

FIG. 9 is a front view of the second image in a sequence shown in FIG. 2 ;

FIG. 10 is a front view of the third image in a sequence shown in FIG. 3 ;

FIG. 11 is a front view of the fourth image in a sequence shown in FIG. 4 ;

FIG. 12 is a front view of the fifth image in a sequence shown in FIG. 5 ;

FIG. 13 is a front view of the sixth image in a sequence shown in FIG. 6 ;

FIG. 14 is a front view of the seventh image in a sequence shown in FIG. 7 ;

FIG. 15 is a right-side of the first image in a sequence shown in FIG. 1 ;

FIG. 16 is a right-side view of the second image in a sequence shown in FIG. 2 ;

FIG. 17 is a right-side view of the third image in a sequence shown in FIG. 3 ;

FIG. 18 is a right-side view of the fourth image in a sequence shown in FIG. 4 ;

FIG. 19 is a right-side view of the fifth image in a sequence shown in FIG. 5 ;

FIG. 20 is a right-side view of the sixth image in a sequence shown in FIG. 6 ; and,

FIG. 21 is a right-side view of the seventh image in a sequence shown in FIG. 7 .

The subject matter in this patent includes a process or period in which an image changes into another image. This process or period forms no part of the claimed design.

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