Generally, when you check into a hotel or rent a car, you will use a credit card to pre-authorize the transaction, which is like a deposit, which will occupy the credit card amount. When you leave the store or return the car for final settlement, the merchant will complete the pre-authorization (pay directly with the pre-authorized amount, and make up for the excess)/cancel it (the landlord will pay in other ways, such as cash), and the time for the amount to be restored is 1-1 after the merchant's operation.

if the merchant doesn't do anything about this pre-authorization, the quota will be automatically released in 3 days for domestic transactions and 15 days for overseas transactions. When the time comes, the landlord can check the change of the credit card available amount (specific way: you can use the mobile phone number reserved at his home, edit the short message: "the last four digits of the 313# card number" to 95533, and will reply to your credit card available amount by the time of sending the short message).