A method of changing a catheter into a distal steering tool catheter includes adding to an existing catheter a tube assembly that passes through the catheter, the tube assembly including an internal tube and an external tube whose distal ends are coupled to each other and which are arranged for longitudinal axial movement relative to one another, and providing a tube manipulator coupled to the tube assembly, which is operative to cause relative axial movement of the internal and external tubes and bending of a distal portion of at least one of the internal and external tubes.