Display screen or portion thereof with transitional graphical user interface

FIG. 1 is 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 the second image thereof;

FIG. 3 is the third image thereof;

FIG. 4 is the fourth image thereof;

FIG. 5 is the fifth image thereof;

FIG. 6 is the sixth image thereof;

FIG. 7 is the seventh image thereof;

FIG. 8 is the eighth image thereof;

FIG. 9 is the ninth image thereof;

FIG. 10 is an enlarged view of the first image thereof with the features shown in broken lines removed;

FIG. 11 is an enlarged view of the second image thereof with the features shown in broken lines removed;

FIG. 12 is an enlarged view of the third image thereof with the features shown in broken lines removed;

FIG. 13 is an enlarged view of the fourth image thereof with the features shown in broken lines removed;

FIG. 14 is an enlarged view of the fifth image thereof with the features shown in broken lines removed;

FIG. 15 is an enlarged view of the sixth image thereof with the features shown in broken lines removed;

FIG. 16 is an enlarged view of the seventh image thereof with the features shown in broken lines removed;

FIG. 17 is an enlarged view of the eighth image thereof with the features shown in broken lines removed; and,

FIG. 18 is an enlarged view of the ninth image thereof with the features shown in broken lines removed.

The outermost broken lines showing the display screen or portion thereof form no part of the claimed design.

The remaining broken lines in the figures depict portions of the transitional graphical user interface which form no part of the claimed design.

The appearance of the transitional graphical user interface sequentially transitions between the images shown in FIGS. 1-9 and in FIGS. 10-18 , respectively. The process or period in which one image transitions to another forms no part of the claimed design.