How to remove a ring from your finger?

I’ve had my wedding ring on for almost 30 years, and need to take it off. Unfortunately, I’ve gained weight recently and cannot remove it by normal means—soap, cooking oil, etc. It will need to be cut off. Anyone have any experience with this? Would I go to a jeweler? Emergency room? Can I do it myself? The back of the band is narrow, but is platinum and hasn’t worn thin at all in 30 years…