I doubt you can switch and maintain your rank in the new country.
you don't lose medals if you haven't changed to that nation before, but i still would be able to do it due to me being maxed rank anyways.
Incorrect, you always lose 2 medals even if you have been with the nation before. I have changed to all 3 many times due to Campaign Ops(I'm trying to complete them all for all nations) and you do lose 2 each time.
She means, you don't lose medals if it's your 1st time changing to said nation. All you have to do is do the initial quest. Every time changing to that nation after the 1st time, you lose 2 medals.
Like me, I started in Windy, I have changed to Sandy for Splitting Heirs before. 1st time was free of medal loss. After that, every time I changed to Windy or Sandy I lose 2 ranks.
If I ever swap to Bastok, 1st time will be free. (thoguh I doubt I ever will)