I tried various options for both removing and hiding various aspects of the above onBlur and pattern attributes, and none of them would work. Either the page would not load, or else I got errors.
I also tried hiding/removing the entire "<div class="lineGroup">" that holds the whole of that phone record, and the form responded by refusing to advance to the next page.
I am thinking that my best option is to do two things:
(A) Make that whole phone field optional,
(B) Remove the effects of that pattern.
How would I accomplish this for I am at present stumped!!