申もうし越こす

godan verb (-su), transitive verb

send word; write to; inform (humble)

Humble verb (謙譲語) used when the speaker sends a message or writes to a superior or someone outside their group. Often used in formal letters or business contexts. The action is performed by the speaker or their in-group toward the recipient.

• 詳しょう細さいが決きまり次し第だい、改あらためて申もうし越こします。

  I will send word again as soon as the details are decided.

• 先せん日じつはお手て紙がみを申もうし越こし、ありがとうございました。

  Thank you for the letter you sent the other day. (humble perspective: the speaker is grateful for the recipient's action of sending, but the verb is used from the speaker's side in a formal acknowledgment)