Remove metadata matching criteria from a comment.

You can match based on the key, or key and value. Removing based on key and value, will keep from removing duplicate metadata with the same key. It also allows removing all metadata matching key, if needed.

Signature

delete_comment_meta( $comment_id, $meta_key, $meta_value = '' )
comment_id
 (int) comment ID
meta_key
 (string) Metadata name.
meta_value
 (mixed) Optional. Metadata value.
Default: ''

Return

(boolean) True on success, false on failure.

Source

function delete_comment_meta($comment_id, $meta_key, $meta_value = '') {
	return delete_metadata('comment', $comment_id, $meta_key, $meta_value);
}
WP Trac GitHub

Link here