How can I cancel my DTV to switch to a Non-B visa, and where can I do this?

To cancel your DTV for a Non-B visa, you need to email the embassy in Ho Chi Minh City (HCM) with your cancellation request and Non-B documentation. This process can be done while you are outside Thailand. Alternatively, you can consult your employer about the possibility of converting your visa within Thailand through the local immigration office. The duration for processing the cancellation will vary depending on the embassy's response.