Withdrawals from an Account can be made via LN or on-chain. However, on-chain withdrawals can only be initiated via the RLS dashboard. The API is to be used for initiating LN Withdrawals. Invoices containing millisatoshi (msat) amounts must be rounded down to the nearest satoshi.
Withdrawals have three potential states: PENDING, SUCCESS, FAIL. A withdrawal is usually in a pending state for only a short period of time, but there are edge cases where withdrawals can be stuck in the lightning network for extended periods of time.
Withdrawals have an embedded withdrawal_details object including specific information about that particular withdrawal. For LN withdrawals this will include the BOLT11 invoice paid.