Tax law changes

Thanks. I do not have an "issue" with filling out the W-4P form. I reviewed it, and it is simple with each of my entries being blank (not applicable) except for step 5 which is my signature. I spoke with two reps at Fidelity yesterday, and the second rep said I could call back to "update" my form within the next 7 days and that would work (versus completing the form, signing, scanning and returning}. My question goes to the correctness of their interpretation of the "new rule" and if it actually applies to RMDs.