hook_footer

trying to replace the footer stuff in _core_footer with my own function i put in _functions.php file.

what happens is that my footer is put in but the old footer still exists on the page

so in this case i have 2 footers.
how to fix this issue to only have 1 footer which is the one i put in the functions

i added
function myfooterfunction(){
//…code
}
add_action(‘hook_footer’, ‘myfooterfunction’);