Display Screen or Portion Thereof with Transitional Graphical User Interface

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

FIG. 1 . 2 is a front view thereof showing a second image in the sequence;

FIG. 1 . 3 is a front view thereof showing a third image in the sequence;

FIG. 1 . 4 is a front view thereof showing a fourth image in the sequence;

FIG. 1 . 5 is a front view thereof showing a fifth image in the sequence;

FIG. 1 . 6 is a front view thereof showing a sixth image in the sequence; and

FIG. 1 . 7 is a front view thereof showing a seventh image in the sequence.

The appearance of the transitional image sequentially transitions between the images shown in reproductions 1 . 1 - 1 . 7 . The process or period in which one image transitions to another image forms no part of the claimed design.

The outermost dot-dashed broken lines represent a display screen or portion thereof and form no part of the claimed design.