Topology - how edit node and edge vertex position

[Michal Seidl]

Hello,
I am trying to figure out, what is correct way to edit 
position/coordinates of nodes and edge vertexes.

While updating edge vertexes can be achieved with function 
ST_ChangeEdgeGeom() by updating whole geometry.

If I try to update start or end point I get 'SQL/MM Spatial exception - 
start node not geometry start point' that is correct by checking the C 
code of function.

So how to change position of start or end point of edge? I would expect 
some function but I am not able to find it.

Thanks for advice Michal S.