How to switch from my galaxy s3 to my iphone 4?

Basically i bought my galaxy s3 and there are times where i miss my iphone and its the same carrier but is there anyway i could switch over? Sorta like the old days when you would switch sim cards to another phone it was easy. Can anyone help? Im just curious

Yes, if you call Verizon (or AT&T or whatever carrier you have) they will walk you through the steps. It's easy, I've done it.

You would have to go to your carrier's store and get a SIM card that fits the iPhone 4, since their SIM cards are smaller than regular SIM cards. That's basically it.