Display Screen or Portion Thereof with Transitional Graphical User Interface

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

FIG. 2 is a second image thereof.

FIG. 3 is a third image thereof; and,

FIG. 4 is a fourth image thereof.

The appearance of the transitional graphical user interface sequentially transitions between the images shown in FIGS. 1 , 2 , 3 , and 4 . The process or period in which one image transitions to another forms no part of the claimed design.

The outer broken lines in the figures show a display screen or portion thereof and form no part of the claimed design. The other broken lines in the figures show portions of the transitional graphical user interface that form no part of the claimed design.