changing post Leave A Comment

Are you saying you want to change the title above the commenting form?

This will be changed in your theme. usually in comments.php. Looks like you are using a premium theme Avada, you will need to get support from the theme developer. You can do so here: https://themeforest.net/item/avada-responsive-multipurpose-theme/2833226/support

Remember to use a child theme when making changes to the theme’s code. Here is more info about child themes. https://developer.wordpress.org/themes/advanced-topics/child-themes/

Hope this info gets you headed in the correct direction.