How to understand the foreign partial priority and how to establish the priority date? It's better to give an example. Thank you.

For example, someone submitted an application for a patent for invention to a foreign country on April 2 this year. In August this year, he thought it was time to occupy the China market, and then he submitted an invention patent application to the China Patent Office. At this time, he can apply at the time of application and ask for foreign priority. In other words, the date when he applied for a patent in China can be regarded as April 2 this year.

If someone else filed a patent application with the same content to the China Patent Office in June this year, because that person has priority, it will be regarded as earlier than the time when the other party filed the patent application, and the patent will be awarded to the first applicant, so the person who wants priority has an advantage.

For another example, in August, someone applied in China and came up with some new plans, which were declared together with the old plans in April. In this way, the old scheme can enjoy priority, but the new scheme can't, which is called partial priority.