The applied patent for appearance has expired. How to apply for an extension?

After the patent expires, you can't apply for extension, you can only apply again. Invention patents are valid for 20 years from the date of filing, and utility models and designs are valid for 10 years from the date of filing. During this period, it is necessary to pay an annual fee to maintain the patent. It should be noted that after the expiration, it will become an open technology and have no legal effect. During the validity period, others can also apply for your patent first ~ ~ ~ So if it is about to expire, you should prepare for the application in advance ~ ~