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 showing a first embodiment of our new design;

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

FIG. 3 is a front perspective view of a pressurized air delivery console that includes the display screen or portion thereof with the graphical user interface of Embodiment 1 in a state of use; and,

FIG. 4 is a front perspective view of a pressurized air delivery console that includes the display screen or portion thereof with the graphical user interface of Embodiment 2 in a state of use.

The broken line rectangles shown in FIGS. 1 and 2 illustrate a display screen or portion thereof which form no part of the claimed design. The broken lines in FIGS. 3 and 4 show a pressurized air delivery console which forms no part of the claimed design.