The ornamental design for a reversibleskirt, as shown and described.
FIG. 1 is a perspective view of the reversible skirt in accordance with my invention;
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is an unfolded view thereof.
The speckled surface indicates difference between inner and outer sides. The broken line showing portions of the skirt is included for the purpose of illustrating environmental structure and forms no part of the claimed design.