Bring an expired envelope back so its signers can finish. Send the new expiry date in expires_at. You get a 204 with no body. The envelope keeps its ID, its status goes back to incomplete, and it shows up in Fetch all envelopes again.
It works on envelopes sent by email with Create or send an envelope (POST /rs/envelope). Embedded signing envelopes, and envelopes sent with POST /rs, return 403. Pending, completed, and canceled envelopes return 400. A daily job marks envelopes expired, so for up to about a day after its expiry_time an envelope still counts as pending and returns 400.
You can't edit signers on an expired envelope. Reactivate it first, then use Edit signer details.
Reactivating an expired envelope is available only on the API Advanced Plan. Reach support or sales for more details.