at least for non-government places, you can go back to them, like a bank, and change the “contact info” they have on you without changing your ARC address.
It’s like 通訊地 . Change that to your friend’s place or get a post office box at local post office for like NT$300 a year. That’s even better, because you can always use that as communications address no matter where your ARC address is.
Also, most banks and telecoms (and probably others) have some “choice” to make of getting all communication through your email address. I have that for my 2 banks. Get online banking set up and add the bank’s App to your smartphone. Can do bank stuff anywhere, even outside Taiwan, of course
You walk into any post office and ask for it.
Bring a local friend. You gotta survive somehow on this island. If alone, someone at the post office will help you out. Don’t be shy.
You have to go to NIA with some kind of document with your new address, like power or gas bill, rental contract, etc.
Now, what I am worried about is the validity of your ARC. Are you here as a student? Or are you working? Please remember that your ARC becomes invalid the moment your reason for it is annulled. Say you do not attend class for a month or get fired. it dors not matter what is printed on the ARC. If it is no longer valid, you need a new reason to get back in the island if you leave the country.
I have a Rep office so It’s kind of work. My arc becomes invalid i guess only if I stay less than 183days per year in taiwan. I’m not even sure about it. I cannot go to NIA because I’m already abroad for one month. My address is the old one, a place I no longer rent. How can I do it?