So for you, henka waza is: If applying ikkyo, and uke straightens his elbow, you make an adjustment bending uke's elbow, so you can again apply ikkyo?
Let's say that for me (and most probably I'm wrong) henka waza is if applying ikkyo and uke straightens his elbow, I make an adjustment to apply ikkyo with his arm straight. As an aside, I don't understand what's wrong with applying ikkyo to a straight elbow. As a henka (for others it may be the kihon) you can apply hiki otoshi to that straightened arm and it still will be ikkyo / ude osae. Even the final pin will be the same. It will just not be the robuse kind of ikkyo.