Generally, you can close your position at any trading time before the expiration, but there are two situations that you can't close your position immediately: the first is that you may not be able to close your position at the daily limit, and then you can't close your position without trading.

Conclusion: If delivery is not made, it is better to follow the main contract or the sub-main contract. When the contract is not closed or there are few transactions, it is generally difficult to close or forced to close, resulting in an increase in losses or a decrease in profits.