A roaming Line

I want to roam my Mtn line 08035317455

Roaming in UK

I dailed the *365*1# to raom my number, but I was asked to update my simcard. How can I update my sim card now that am in USA?

I need to activate roaming on my line in the US. I did not activate roaming before leaving Nigeria. Is there a way to still get that done while I'm here? # Activating roaming...