Formal to Superior
Workplace · Email
You
誠に恐れ入りますが、提出期限を〇日ほど延長いただくことは可能でしょうか。
まことにおそれいりますが、ていしゅつきげんを〇かほどえんちょうをいただくことはかのうでしょうか。
I sincerely apologize for the inconvenience, but would it be possible to extend the submission deadline by approximately [X] days?
Romaji: Makoto ni osoreirimasu ga, teishutsu kigen wo XX ka hodo enchō itadaku koto wa kanou deshou ka. / Reply Romaji: Jijou wa wakarimashita. Kokonoka made ni onegai shimasu.
Reply
事情はわかりました。9日までにお願いします。
じじょうはわかりました。ここのかまでにおねがいします。
I understand the situation. Please have it ready by the 9th.
Gesture & etiquette
This is a written (email) request. Place it early in the email body after the opening greeting. Be specific: state the current deadline, the extension requested, and a brief reason. Offer an alternative if the extension cannot be granted: 'Moushiwake gozaimasenga, manzoku dekinai baaibawa' (If a full extension is not possible, even [shorter time] would help greatly).
Extension requests require maximum humility in Japanese business communication. 'Makoto ni osoreirimasu' (I am truly mortified to ask) is the most formal apology for an inconvenient request. Always specify exactly how many days you need — vague requests ('a bit more time') create confusion and signal poor planning. Provide a brief reason if appropriate.