You can convert to F-1 but H1B will not reset
You may convert to F1 after 6 years on H1B, however, your H1B clock will not reset until you are physically out of the country for 1 year.
Exception applies if you have immigration petition pending and labor cert was filed longer than 365 days according to AC21. In that case, you may file for H1-B extension in 1 year increments.