During the preview period, testers will be able to change their PSN names as many times as they want. If you do decide to change your PSN name (which is probably a majority of you), you will have the option to display either your brand new ID or your old one, for recognition's sake. However, unlike the previous setting, this option is only available while applying the change and not after.
With each huge update that hits the PlayStation network, many PSN users have had no problem being vocal about there displeasure that there still isn't a way to change those old gamertags.
A post on the PlayStation Blog runs down the details for how the name change service will work. Non-PlayStation Plus members will be charged $9.99 per additional name change, while PlayStation Plus members only have to pay $4.99. The Nintendo Switch doesn't let you change your base Nintendo Account username, but it does make it easy (and free) to change the "nickname" that appears to other players online. Reverting back to an old ID will resolve most issues caused by the ID change. However, the full name change feature is due to launch in early 2019. We'll get a list of officially compatible games at some point in the future. It does warn that not all games and applications for PS4, PS3, and PS Vita will support the change and you may encounter some issues using them with a new ID.
KitGuru Says: I've been wanting to change my name for quite some time after my online moniker was inexplicably denied. If you wish to revert, you can do so for free, though you can only do this once during the preview program.