can i change the sim card in an iphone 4 for verizon

Verizon has been known to unlock the SIM slot for international use. My understanding is the general requirements are some minimum time under contract, and a perfect payment record. So call them and ask about it. Its certainly not an uncommon thing for them to do with their world phones (and of course, here in the USA, it still will only work on their network anyway).

there are even online articles telling you how to proceed

http://www.zdnet.com/blog/cell-phones/international-travelers-here-is-how-to-sim -unlock-your-verizon-apple-iphone-4s/6712

A Verizon iPhone 4 cannot be used on any other carrier. The iPhone 4S can be unlocked for overseas use, which is what I believe that Michael is thinking of, but an iPhone 4, no.

Regards.

The Verizon iPhone 4 is a pure CDMA phone. It does not have a SIM slot and there is no way to use it with any carrier other than Verizon.

You are correct - I missed the simple "4" part of that first post.

Sorry fatcubed - you will have to wait until you've been under contract with your iPhone 5 to do as I suggested (but then you can get the iPhone 5 SIM slot unlocked for international use).

P.S. are you upgrading to the iPhone 5 (using a Verizon upgrade eligibility and signing a new 2 year contract)? If so, give them a call as soon as you get the iPhone 5 as they may count your previous time under contract as sufficient to qualify for unlocking - worth a call to their customer service at least to find out.