A technique is provided for engaging and disengaging an upper completion with a lower completion positioned in a wellbore. The upper completion comprises an upper communication line, and the lower completion comprises a lower communication line. The upper completion is mechanically latched with the lower completion and the communication lines are coupled in a manner that enables selective engagement and disengagement. A communication line union is used to connect the upper communication line and the lower communication line in a plurality of rotational orientations of the upper completion relative to the lower completion.