IBKR's margin compliance policy does not provide for an extension to a margin call. In the case of a margin violation/deficit, the account in deficit will be immediately subject to liquidation. Automated liquidations are accomplished with market orders and any/all positions in the account can be liquidated. There are cases where, due to specific market conditions, a deficit is better addressed via a manual liquidation.
More information on margin trading at IBKR can be found on our website.