The ornamental design for a retractableentrypartition, as shown and described.
FIG. 1 is a front perspective view of the design in a closed position; and,
FIG. 2 is a front perspective view of the design in an open position.
The rear is a mirror image of the design shown in FIGS. 1 and 2. The top, bottom and sides are flat, devoid of surface ornamentation, and form no part of the claimed design. The dotted lines are shown for environmental purposes only and form no part of the claimed design.