Display Screen or Portion Thereof with a Graphical User Interface

FIG. 1 is a front view of a display screen or portion thereof with a graphical user interface;

FIG. 2 is a front view of a second embodiment thereof;

FIG. 3 is a front view of a third embodiment thereof;

FIG. 4 is a front view of a fourth embodiment thereof;

FIG. 5 is a front view of a fifth embodiment thereof;

FIG. 6 is a front view of a sixth embodiment thereof;

FIG. 7 is a front view of a seventh embodiment thereof;

FIG. 8 is a front view of a eighth embodiment thereof; and,

FIG. 9 is a front view of a ninth embodiment thereof.

The broken lines around the perimeter show a display screen or portion thereof and form no part of the claimed design. The dash-dot-dash broken lines illustrate boundaries of the claimed design. The areas between the perimeter broken lines and the dash-dot-dash broken lines form no part of the claimed design.