Do I need to go to the immigration office myself to correct the 'admit until' stamp date on my passport in Thailand?

Just a quick question... I tried to search the right post since I'm sure this must have been asked often, but I couldn't.

For correction of "admit until" stamp date, does the passport holder needs to go to immigration office by her/himself? Or can ask for someone else, like a friend? Or any other way to do?

I think in anyway better to go before the earlier date of current stamped date or 'the date supposed to be'...