[XQuery Update Newbie] Rename all element nodes (in no namespace) to the same name, but in a namespace?

[Costello, Roger L.]

Hi Folks,

FitnessCenter.xml contains elements in no namespace:

<?xml version="1.0"?>
<FitnessCenter>
    <Member level="platinum">
        <Name>Jeff</Name>
        <FavoriteColor>lightgrey</FavoriteColor>
    </Member>
    <Member level="gold">
        <Name>David</Name>
        <FavoriteColor>lightblue</FavoriteColor>
    </Member>
    <Member level="platinum">
        <Name>Roger</Name>
        <FavoriteColor>lightyellow</FavoriteColor>
    </Member>
</FitnessCenter>

I want to change each element to be in a namespace:

<?xml version="1.0"?>
<gym:FitnessCenter xmlns:gym="http://www.gym.com">
    <gym:Member level="platinum">
        <gym:Name>Jeff</gym:Name>
        <gym:FavoriteColor>lightgrey</gym:FavoriteColor>
    </gym:Member>
    <gym:Member level="gold">
        <gym:Name>David</gym:Name>
        <gym:FavoriteColor>lightblue</gym:FavoriteColor>
    </gym:Member>
    <gym:Member level="platinum">
        <gym:Name>Roger</gym:Name>
        <gym:FavoriteColor>lightyellow</gym:FavoriteColor>
    </gym:Member>
</gym:FitnessCenter>

I figured that I could simply do a rename:

for $i in doc('FitnessCenter.xml')//*
    return rename node $i as QName('http://www.gym.com', name($i))

Here's the error message I get from Saxon:

    New name conflicts with existing namespace binding

What's the correct way to do this please?

/Roger