Allows you to rename any group message in iOS 14. Long press on a message thread and press Change Group Name to rename it. To remove the group name, leave it blank.
Note that the name change function of iOS will display "You named the conversation _____" in the thread on your phone. However:
If the group message is a SMS/MMS thread (green), this notification will only be visible to you. No one else will get a notification of the name change.
If the group message is an iMessage thread (blue), all recipients will get a notification of the new name and their group name will change as if you did it from the info menu.