Atomic changes allow you to stage all of your record changes and then execute them all at once. Rather than deleting records and then racing to add the replacement records and putting your site availability on the line, you can remove records and add new ones simultaneously.
For example: If you need to change a record from ANAME to CNAME, Atomic Changes allow you to easily switch your record without any downtime.
NOTE: You must Commit Your Changes after you have removed and added all necessary records.