override functions.php in child theme: where am I wrong?!?

I need to modify the functions.php on my father theme in order to change “Continue reading” link and “view more text”.

Here’s the original code:

function bavotasan_front_page_render() {
	global $wp_query, $paged;
	?>
	<?php while ( have_posts() ) : the_post(); ?>
		<?php if ( is_front_page() ) { ?>
		<div class="item">
			<figure class="effect-julia">
				<?php
				if ( has_post_thumbnail() )
					the_post_thumbnail( 'home' );
				else
					echo '<img src="' . BAVOTASAN_THEME_URL . '/library/images/no-image.jpg" alt="" />';
				?>
				<figcaption>
					<h2><?php the_title(); ?></h2>
					<div>
						<p><?php echo wp_trim_words( strip_shortcodes( get_the_excerpt() ) , 10 ); ?></p>
						<p class="more-link-p"><?php _e( 'Continue reading <span class="meta-nav">&rarr;</span>', 'destin' ); ?></p>
					</div>
					<a href="<?php the_permalink(); ?>"><?php _e( 'View more', 'destin' ); ?></a>
				</figcaption>
			</figure>
		</div>
		<?php } else { ?>
			<?php get_template_part( 'content', get_post_format() ); ?>
		<?php } ?>
	<?php endwhile; ?>
	<?php
}

add_action( 'wp_head', 'bavotasan_styles' );

I tried with remove_action as read on varios places but I don’t know where am I wrong. Every time I get that error:

“Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, ‘altered_bavotasan_styles’ was given in /web/htdocs/www.crea11.it/home/studiocrea/wp-includes/plugin.php on line 496”

and here’s the child functions.php commands. what am I mistaking?

function dequeue_bavotasan_styles() {
  remove_action( 'wp_head', 'bavotasan_styles' );
}
add_action('after_setup_theme', 'dequeue_bavotasan_styles');

function altered_bavotasan_front_page_render() {
	global $wp_query, $paged;
	?>
	<?php while ( have_posts() ) : the_post(); ?>
		<?php if ( is_front_page() ) { ?>
		<div class="item">
			<figure class="effect-julia">
				<?php
				if ( has_post_thumbnail() )
					the_post_thumbnail( 'home' );
				else
					echo '<img src="' . BAVOTASAN_THEME_URL . '/library/images/no-image.jpg" alt="" />';
				?>
				<figcaption>
					<h2><?php the_title(); ?></h2>
					<div>
						<p><?php echo wp_trim_words( strip_shortcodes( get_the_excerpt() ) , 10 ); ?></p>
						<p class="more-link-p"><?php _e( 'Cooontinue reading <span class="meta-nav">&rarr;</span>', 'destin' ); ?></p>
					</div>
					<a href="<?php the_permalink(); ?>"><?php _e( 'Viooooew more', 'destin' ); ?></a>
				</figcaption>
			</figure>
		</div>
		<?php } else { ?>
			<?php get_template_part( 'content', get_post_format() ); ?>
		<?php } ?>
	<?php endwhile; ?>
	<?php
}

add_action( 'wp_head', 'altered_bavotasan_styles' );