Changing sims with factory unlocked Iphone 4?

[lloyd]

I work for the U.S. State Department in a job that requires me to move around every year and everywhere I go I'm always using a phone (not a very good quality one at that) that is locally purchased with a locally tracked sim card. My payments on each phone have varied so much and calls to the United States are very expensive through a lot of foreign phone companies. I decided to go with a Mobal account because calls in country are cheap and the signal is always reliable. To remedy the issue of always having a subpar Embassy issued phone (more often than not they're first generation models of something where the buttons hardly work and I can potentially pay up to $700.00 for three months usage, and a good number of the calls get dropped) so I'd always have my own phone that I could use for both work and personal calls at a reasonable price. I recently purchased an unlocked Iphone 4 (Factory Unlocked) and to set it up I'm trying to use my embassy phone sim card. When my Mobal sim comes in a few weeks will I be able to just switch the cards and reset the phone or will trying to switch cards cause issues? Thank you for your responses!