Change phone number in LINE app to a different country [on hold]

I’m trying to change the phone number registered in LINE app

The problem is, there seem to be no way to switch country ; from Japan to USA for instance.

There are some old posts on forums about this, requesting to uninstall and reinstall LINE… which always goes with problems (loss of some data, chats, …).

Nowadays, is there a lossless way to do this, via the app or via a PC/Mac?

_{Note: the issue is about LINE app on an iPhone, but the problem is same on Android.}