A few photos would help.
Take them off and replace with https://www.amazon.com/s?k=chair+roller+balls&i=garden&ref=nb_sb_noss
You should be able to find the same that you have at a home improvement store. They will be able to help you with the information on how to replace.
Yes, you can easily remove them and purchase new roller balls at a local hardware store. They are easy to put on. :)