Under what circumstances will the TTAB grant a motion for an extension?
The motion will be granted if good cause is shown. Examples are given in section 509.01(a) of the TBMP at the link below.
Ask for the extension before it is due, and state a good cause. Probably granted.
I'm not your attorney; my answer includes assumptions. If you want me to be your attorney, I'm easy to find.
Years licensed, work experience, educationLegal community recognition
Peer endorsements, associations, awardsLegal thought leadership
Publications, speaking engagementsDiscipline