Knit the pocket separate and put the sts on hold.
Work the front piece until position for the pocket.
Now work the sts from center front edge to where the pocket starts, put the same number of sts as there are on the pocket on a st holder or waste yarn for pocket opening, knit the sts from the pocket and then remaining sts on row. Continue to work front piece as before on all sts.
When finished put sts from holder on needle. Knit an edge and then bind off. Sew sides of pocket edge to front. Sew pocket lining to wrong side in such a way that the sts do not show on right side.