Display Screen or Portion Thereof with an Animated Graphical User Interface

FIG. 1 is a front view of a display screen or portion thereof showing a first frame of an animation; FIG. 2 is a front view of a display screen or portion thereof showing a second frame of an animation; and, FIG. 3 is a front view of a display screen or portion thereof showing a third frame of an animation. The outermost broken lines shown in the FIGURES illustrate portions of the display screen or a portion thereof with a graphical user interface that form no part of the claimed design. The other broken lines in the FIGURES show portions of the graphical user interface that form no part of the claimed design. The appearance of the display screen or portion thereof with animated user interface transitions sequentially between the views shown in FIGS. 1 , 2 , and 3 , respectively. The process or period in which one FIGURE transitions to another forms no part of the claimed design.