session_id returned earlier along with the OTP to complete activation.session_id: Activation session identifierotp: 4 digit OTP sent to the useridempotency-key: Unique key to ensure idempotent requestscard_status: Resulting status of the card after activation is confirmed404 CARD_NOT_FOUND/CARD_ISSUANCE_NOT_FOUND: Card or activation session missing412 CARD_EXPIRED/ACTIVATION_NOT_ALLOWED: Card expired or not allowed to activate400 ACTIVATION_FAILED: OTP validation failed or activation could not finish503 SERVICE_UNAVAILABLE: Backend temporarily unavailable