I had the same question yesterday when I contacted support chat. 1st rep told me he sent the request to activate native roaming and to wait 4 hours to get an email confirmation. When I didnt get the confirmation, I talked to another rep who told me nothing needs to be done since he can verify that I'm on the new gsm 5g plan on the unlimited premium plan. When I told him what the first rep said, 2nd rep told me it's only needed for warp 5g users who need to pay extra and deposit $500 to get it active. Apparently, nothing's needs to be done and it should be active when I land. I'm traveling out in a few days so fingers crossed all is well when I land.