To Modify a Vertex of a Fence Orthogonally

Select the Modify Fence tool ( Drawing > Home > Selection > Fence Tools split button).
Set the tool setting Modify Mode to Vertex.
Select the vertex to move.
Enter a data point to define the new vertex position.
Do one of the following:

Reset to accept the modification.

or
Repeat step 4.

Modify Fence Vertex Orthogonally