Wanna Change Dermatologist to iGraft Clinic

To change the custom post type's slug name you actually need to make changed in theme files. Dermatologist WordPress theme use doctors, services as public custom post types which have slugs and can be replaced as per demand. 

First of all locate the file where custom post type is being registered. In dermatology WordPress theme post types files are located in wp-content >> themes >> dermatology >> lib >> admin >> custom-post-types  edit file for which you want to replace the Slug. Let's say we want to replace custom post type slug for dermatologist. Edit dermatologist.php and find the code below. 

$args = array(
			'labels'             => $labels,
			'description'        => esc_html__('Dermatologists Section', 'dermatology'),
			'public'             => true,
			'publicly_queryable' => true,
			'show_ui'            => true,
			'show_in_menu'       => true,
			'query_var'          => true,
			'rewrite'            => array('slug' => esc_html__('dermatologist', 'dermatology')),
			'capability_type'    => 'post',
			'has_archive'        => true,
			'menu_icon'			 => 'dashicons-visibility',
			'menu_position'      => 35,
			'taxonomies'		 => array(esc_html__('dermatologist_group', 'dermatology')),
			'supports'           => array( 'title', 'editor', 'thumbnail')
		);

These are the arguments for custom post type register. Here in 'rewrite' option you can replace the slug from dermatologist to anything like team-member or doctor or anything. 

Similarly on same file you can replace dermatologist_group slug also for that you can edit the slug in code below. 

$args = array(
			'post_type'			=> array(esc_html__('dermatologist', 'dermatology')),
			'hierarchical'      => true,
			'labels'            => $labels,
			'show_ui'           => true,
			'show_admin_column' => true,
			'query_var'         => true,
			'rewrite'           => array( 'slug' => esc_html__('dermatologist_group', 'dermatology')),
		);

change rewrite dermatologist_group to anything you want that's it. Nothing else required to change in it slugs will work as per your requirements in this matter.