Not having gotten an answer here, once the statement period starting 8/20 was under way, I sent a secure message. The first reply didn't answer the main question of which month this statement would close after I requested a change. When I followed up, they said if I request it now (make new due date the 9th), the current statement would close 9/12. If this is right, does it look correct that I can put the date change request in after 9/12 and get that statement to close 10/12, due 11/9?