[jdom-interest] Editing Attributes

[Bashiro]

Hello,

I wonder if one has the following in XML file example;

<contact_properties   user_name="bashiro" address="here" phone="3333" hobby="dGVzdDI" />
  <contact_properties user_name="test" address="there" phone="444" hobby="dGVzdDIno" />
  <contact_properties user_name="test2" address="there 2" phone="4446" hobby="-dGVzdDIno" />

Username is unique so its the primary  Key.

If I want to edit address of say bashiro, I search for bashiro and when found,  the address attributes of bashiro is set to the
new attributes. 
My question is; should the whole bashiro be removed and then the new attributes set, or one can simply edit only address ?

Bashiro
Drammen-Norway