As for whether it can be modified, the answer is that there is an opportunity to modify it, but there is a time limit for modification, as follows.
The time for active modification of an invention is three months from the date when the invention patent applicant files a request for substantive examination and receives the notice of entering the substantive examination stage issued by the State Intellectual Property Office.
In addition, modifications are not arbitrary and need to be within the scope of the original application documents. That is to say, you cannot modify it to add new technologies, improvements, etc. The modifications must have corresponding places in the original application documents.
In addition, when you receive review comments later, you can make modifications based on the review comments.
In addition, if what you want to modify is to change the technology itself, you can request priority and then apply for a new patent within 12 months from the filing date of the previous patent.