Sometimes when modelling, especially when copying and pasting multiple objects or inserting lanes into the middle of an existing diagram the links may make connections that aren't quite as you desire. If this does occur, simply use the 'Relink All' button from the actions menu to reset all the links to their most logical connection points. As seen below.

If you link two objects and decide you wish to reverse the direction, simply use the 'Reverse' button from the actions menu to reverse the link direction.