How to bypass required fields in form validation function of a module?
If you are building your own form, you need to remove '#required' =&gt; TRUE, from field to bypass validation or assign FALSE value.

Example with required field:

$form['title'] = array(
  '#type' =&gt; 'textfield', 
  '#title' =&gt; t('Subject'), 
  '#default_value' =&gt; 'whatever', 
  '#size' =&gt; 60, 
  '#required' =&gt; TRUE, // remove this if you want to bypass or give it FALSE value
);


Check Form API Reference for more details

Now you can do the same for existing form by alter the form using hook_alter_form and unset required attribute or assign FALSE value.

Example:

function mymodule_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  if($form_id == 'FORM_ID') {
    $form['FIELD_NAME']['#required'] = FALSE;
    // or
    unset($form['FIELD_NAME']['#required']);
  }
}