You can’t get a regrade unless your score was below a 3
Here is the link from the CB:
https://apcentral.collegeboard.org/pdf/ap-testing-guide-2020.pdf
See page 10. The process in past years is not applicable this year.
For this year., the process is: if the score was a 1 or a 2, the teacher (who has a copy of the responses) can ask for a regrade if s/he believes the answers warranted a higher score. The student cannot petition directly to the CB for a regrade. If the score was 3+, the CB will not regrade.