Can I change a cpnav group phrase by php ?

[EquinoxWorld]

Ok. I just got done reading this tutorial (https://vborg.vbsupport.ru/showthread.php?t=83122); which is a bit old but apparently still valid for what I want. How about this for what I want to accomplish...
I have this file which is used for one of the contest options for example. If the user has not entered a new name for the contest to "activate" it then he get's the form to enter the name if not he get's the rest of the options. Now with this when the user enters a name and saves the phrase will be changed and the other options would appear. My question would be how do I make the form "submit" button run the SQL commands to change the phrase once the user hit's said button?

Here's my code:

PHP Code:

if ($_REQUEST['do'] == 'contest1')
{
    
    if ($vbphrase['cotw_cpnav_contest1'] == 'Contest 1'){
 
print_cp_header();

print_form_header('cotw');
print_table_header($vbphrase['cotw_cpnav_contest1']);

print_input_row('Enter the name of your contest', 'inputname'); 

# table rows

print_submit_row("Submit!");  
 
print_cp_footer();
}


else {
    print_cp_header();

print_form_header('cotw');
print_table_header($vbphrase['cotw_cpnav_contest1']);

//HERE GOES ALL THE OTHER OPTIONS WHICH I HAVE YET TO PUT///JUST FOR EXAMPLE PURPOSES//
# table rows

print_submit_row("Submit!");  
 
print_cp_footer();
}
} 


P.S: Contest 1 is the default text for that phrase. Therefore if the script knows it's the default then it knows that the user has yet to name that contest.