Here is a modification of the Line into a Polyline to make it more useful. Usually when you want to turn a line into a polyline, you also want to join it to several other connecting lines at the same time. make a new command macro called Line2Pline with the following action, then drag it under Line in the Double Click Actions section:
^C^C_pedit;;j;
(there is no space after the )
Double click a line, it makes it a pline and leaves you in pick mode to add individually or with a crossing window other lines to join. Right click twice when you are finished.