Joanna is going overseas for six months and wants to have a local phone number with local SIM. She wants a dedicated phone with dual SIM cards. Leo says that's a good idea and he recommends the One Plus Two. Right now is a great time to get it because of their Black Friday sales, which means she won't need an invite. She shouldn't buy from a carrier, though, because it'll be locked. She'll want it unlocked.
Microsoft's Lumia 950 is a Windows phone that also has dual SIMs and a great camera, but she'll only have access to a limited number of apps. Joanna should check out this article on the 20 Best Dual SIM smartphones from PCAdvisor.co.uk.