I believe the CoordinateReplacer transformer can do just that.

Hi @amandab, I don't think there is a transformer to do that at once, but you can use the CoordinateRemover to remove a vertex from a line and the VertexCreator to add a vertex at the end of a line. So, assuming that attributes storing coordinates of new start and end nodes have been merged to the line features already, this procedure may be a possible way.

1. CoordinateRemover: Remove the last vertex.
2. 
   VertexCreator (Mode: Add Point): Add the new end node.
3. 
   Orientor: Reverse the orientation.
4. 
   CoordinateRemover_2: Remove the last vertex.
5. 
   VertexCreator_2: Add the new start node.
6. 
   Orientor_2: Reverse (Restore) the orientation.

Hi @amandab,

In case you are working with a database format and the line ID and new XY are identical, you can create new lines from the points and update the existing geometry in the database with the help of the common ID.

The VertexCreator has a mode Replace Point at Index which should do want you want.

Thanks everyone, those are quite a few options to try, that's great. This was my first post, I'm pleasantly surprised at the quick response!

Ok, looks like this worked:

Extracted the coordinates for the points (specify coordinate), and the lines (All Coordinates), featuremerged them together (using both merged and unmerged in case some lines were missing a start or end matching point) and created new attributes to make sure the xy for the start points and end points were in individual fields. Then used VertexCreator to create a new start point (replace point at index, for index = 0), and used VertexCreator to create a new end point (replace point at index, for index = -1). That really seems to have done the trick.

Thanks again everyone!