You can remove a backup of iPhone from the list of backups in iTunes. You may want to do this, for example, if a backup was created on someone else’s computer.
In iTunes, open iTunes Preferences.
Windows: Choose Edit > Preferences.
Mac: Choose iTunes > Preferences.
Click Devices (iPhone does not need to be connected).
Select the backup you want to remove, then click Delete Backup.
Confirm you wish to remove the selected backup by clicking Delete Backup.
Click OK to close the iTunes Preferences Window.