Can I change my Non-O Thai Child extension to a marriage extension without leaving the country?

The user has been on a yearly Non-O Thai Child extension for 8 years and is inquiring whether they can change their extension to a marriage-based visa without leaving Thailand during their next renewal in March. According to the comments, it is generally possible to apply for a 1-year extension under a different reason, such as marriage, but it's advisable to verify specific requirements with the local immigration office and consult the employer ahead of time.