You can edit the path (outline) of a single object. (Grouped objects must be ungrouped first)

Select the object then press Ctrl + E or select Edit Object from the Edit menu.

Any fill colour disappears, and blue blobs appear at the end of each line element.

You can click on any of these and, by holding the left mouse button down, drag it to a new position.

Repeat if necessary with the other points.

Click anywhere away from the object to end the edit.