Clear a BLOCKED PIN, restoring the cardholder's existing PIN without changing it. A PIN blocks after three consecutive incorrect entries; until it is cleared, PIN-verified transactions decline.

Unblocking is idempotent and safe to call on a card whose pinStatus is already OK. It has no effect on a card with no PIN set, which returns 409 — set a PIN with POST /cards/{id}/set-pin instead.

Each card permits one unblock attempt per rolling seven days. Further attempts return 409 PIN_CHANGE_REQUIRED with details.pinUnblockAvailableAt. Change the PIN through either PIN-entry flow to recover sooner; changing the PIN does not reset the unblock allowance.

Only request an unblock after authenticating the cardholder and receiving their explicit request. Do not automatically unblock after a declined transaction.

Grid supports online PINs only. Offline PIN cards are not supported. Read GET /cards/{id} to check pinStatus.

Every call is audit-logged with the requesting actor.