Display Screen or Portion Thereof with a Graphical User Interface

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

FIG. 2 is a front view of a second embodiment of a display screen or portion thereof with a graphical user interface showing my new design;

FIG. 3 is a front view of a third embodiment of a display screen or portion thereof with a graphical user interface showing my new design;

FIG. 4 is a front view of a fourth embodiment of a display screen or portion thereof with a graphical user interface showing my new design;

FIG. 5 is a front view of a fifth embodiment of a display screen or portion thereof with a graphical user interface showing my new design;

FIG. 6 is a front view of a sixth embodiment of a display screen or portion thereof with a graphical user interface showing my new design; and,

FIG. 7 is a front view of a seventh embodiment of a display screen or portion thereof with a graphical user interface showing my new design.

The broken lines are included for the purpose of illustrating unclaimed portions of the display screen or portion thereof with a graphical user interface and form no part of the claimed design.