how do I unlock my straighttalk iphone 5s to activate service again using straight talk

[Lisa Michelle]

My daughter has a straight talk iphone5s but just bought a new iPhone 6 whatever. She is giving me her previous one. I can access Itunes when plugged into my computer. I went in with passwords and removed the phone from iTunes account. Now, want to go to Walmart and get it turned on (with a straight talk card) and do I have to purchase a sim or something? Ready to go now. Thanks

 

[hang-the-9]

If you are going to the store to get it swapped over to your account, they will take care of the activation for you there.