I need to modify a block class called in a phtml file, this is the `customer.phtml` file:

    <?php
    // @codingStandardsIgnoreFile
    
    ?>
    <?php if($block->customerLoggedIn()): ?>
        <li class="customer-welcome">
            <span class="customer-name"
                  role="link"
                  tabindex="0"
                  data-mage-init='{"dropdown":{}}'
                  data-toggle="dropdown"
                  data-trigger-keypress-button="true"
                  data-bind="scope: 'customer'">
                <span data-bind="text: customer().fullname"></span>
                <button type="button"
                        class="action switch"
                        tabindex="-1"
                        data-action="customer-menu-toggle">
                    <span><?php /* @escapeNotVerified */ echo __('Change')?></span>
                </button>
            </span>
            <script type="text/x-magento-init">
            {
                "*": {
                    "Magento_Ui/js/core/app": {
                        "components": {
                            "customer": {
                                "component": "Magento_Customer/js/view/customer"
                            }
                        }
                    }
                }
            }
            </script>
            <?php if($block->getChildHtml()):?>
           <div class="customer-menu" data-target="dropdown">
                <?php echo **$block->getChildHtml()**;?>
           </div>
            <?php endif; ?>
        </li>
    <?php endif; ?>

I'm interested in the block beetween the `div` with class `customer-menu`.
I want to remove `<ul class="header link">` tag but not their `li` children, this `ul` tag is inside the `<ul class="header link">` when someone is logged in.