Answer:
January 1, 2024
Step-by-step explanation:
The IRS states that any S corporation that has been converted to a C corporation and wants to turn back into an S corporation again, must wait at least until the fifth tax year to do it.
In this case, the S corporation was converted to a C corporation in 2019, so 2019, 2020, 2021, 2022 and 2023 must pass before it is converted again into an S Corporation. It can be converted again at the beginning of 2024 (the fifth year).