dom_import_simplexml

<?

$data =
<<<XML
<?xml version="1.0"?>
<people>
    <person xmlns:a="https://osbo.com">
        <a:first a:class="myclass" a:id="myid" a:title="mytitle">first</a:first>
        <a:last>last</a:last>
        <a:age>age</a:age>
    </person>
    <person xmlns:b="https://osbo.com">
        <b:first b:class="myclass" b:id="myid" b:title="mytitle">first</b:first>
        <b:last>last</b:last>
        <b:age>age</b:age>
    </person>
    <person xmlns:c="https://osbo.com">
        <c:first c:class="myclass" c:id="myid" c:title="mytitle">first</c:first>
        <c:last>last</c:last>
        <c:age>age</c:age>
    </person>
</people>
XML;

$node = simplexml_load_string($data);

$return = dom_import_simplexml($node);

print_r($return);

DOMElement Object
(
    [tagName] => people
    [className] => 
    [id] => 
    [schemaTypeInfo] => 
    [firstElementChild] => (object value omitted)
    [lastElementChild] => (object value omitted)
    [childElementCount] => 3
    [previousElementSibling] => 
    [nextElementSibling] => 
    [nodeName] => people
    [nodeValue] => 
    
        first
        last
        age
    
    
        first
        last
        age
    
    
        first
        last
        age
    

    [nodeType] => 1
    [parentNode] => (object value omitted)
    [parentElement] => 
    [childNodes] => (object value omitted)
    [firstChild] => (object value omitted)
    [lastChild] => (object value omitted)
    [previousSibling] => 
    [nextSibling] => 
    [attributes] => (object value omitted)
    [isConnected] => 1
    [ownerDocument] => (object value omitted)
    [namespaceURI] => 
    [prefix] => 
    [localName] => people
    [baseURI] => 
    [textContent] => 
    
        first
        last
        age
    
    
        first
        last
        age
    
    
        first
        last
        age
    

)