Display screen or portion thereof with transitional graphical user interface

A portion of the disclosure of this patent document contains material to which a claim for copyright is made. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but reserves all other copyright rights whatsoever.

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

FIG. 2 is a second image thereof;

FIG. 3 is a third image thereof;

FIG. 4 is the first image in a sequence for a display screen or portion thereof with transitional graphical user interface showing a second embodiment of the new design;

FIG. 5 is a second image thereof;

FIG. 6 is a third image thereof;

FIG. 7 is the first image in a sequence for a display screen or portion thereof with transitional graphical user interface showing a third embodiment of the new design; and,

FIG. 8 is a second image thereof.

The appearance of the transitional graphical user interface sequentially transitions between the images shown in FIGS. 1-3 ; FIGS. 4-6 ; and FIGS. 7-8 . The process or period in which one image transitions to another forms no part of the claimed design.

The outermost broken lines illustrate a display screen or portion thereof and form no part of the claimed design. The remaining broken lines, including the text reciting “OS Name,” illustrate portions of the graphical user interface that form no part of the claimed design.