Can my husband leave Thailand to apply for a Non-B visa without canceling his Non-O visa?

Hi everyone! I have a Non-O visa question.

My husband got a Non-O visa in South Africa. He has yet to extend it from the initial 90 days to the full year. We are already in Thailand. He recently got a job and needs to do a visa run to get a Non-B visa. His visa department has said he doesn't need to cancel the Non-O at immigration and he can just leave the country and get the non-B.

Years of experience in this country has taught me to always double check 😂

Can someone confirm this information? I know we normally need to cancel the previous visa before getting a new one, but don't know if this is any different.

Thanks!