I am using two wp_logout_url() echoes on page.
The first one is used in header.php custom theme file, second one is used in another page template file (page-[customslug].php).

On that page i have a form to edit user profile data.
Sending this form cause on result page “headers already sent” error.
To avoid this problem i must remove one from those two lines where i use <?php echo wp_logout_url(); ?>.

<?php 

get_header();  <--- first wp_logout_url();

/* page-[custom-slug].php content */ <--- second wp_logout_url();

get_footer; 

?>

Why i can’t use multiple logout links on one page?

IMPORTANT:

This is how i retrieve the sended form data:

<?php 

if ( isset($_POST['btnname']) ) : 

   // saving data stuff

else : 

   // page-[custom-slug].php content

endif;

?>