After applying for an electronic patent, can I apply in writing again? If not, how to cancel the electronic application and how long will it take?

1, no, no matter whether you entrust a patent agency or not, you can't apply in writing after applying for a patent electronically through the patent electronic application system.

If you re-submit a patent application to China National Intellectual Property Administration, you can apply in writing. But the premise is that the previous electronic application has not been made public or announced.