TWEAK_MATCH_LINE moves a point on a matchline to a different vertex of the same workplane.
+--------------<-----------------+ | | ---->(TWEAK_MATCH_LINE)--+--|match_line|--|match_vertex|--+---->
TWEAK_MATCH_LINE [specify match line] [specify new vertex]
Note that you do not need to identify the source vertex. OneSpace Designer recognizes that the source vertex is on the same workplane, and on the specified matchline.