XML Golang Processing

I am trying to process XML files with complex structure in Go using the standard encoding / xml package, change the values ​​of a node pair, and save an alternate file. For example:

<description>
    <title-info>
        <genre>Comedy</genre>
        <author>
            <first-name>Kevin</first-name>
            <last-name>Smith</last-name>
        </author>
        <movie-title>Clerks</movie-title>
        <annotation>
            <p>!!!</p>
        </annotation>
        <keywords>comedy,jay,bob</keywords>
        <date></date>
    </description>
</title-info>

      

        
        
        
      

    

And many more fields. I would like to change node:

<author>
    <first-name>Kevin</first-name>
    <last-name>Smith</last-name>
</author>

      

        
        
        
      

    

to

<author>
    <first-name>K.</first-name>
    <middle-name>Patrick</middle-name>
    <last-name>Smith</last-name>
</author>

      

        
        
        
      

    

However, since the files are massive and use 50+ tags, I really don't want to describe the complete structure to untie them, so I have

type Result struct {
    Title   string   `xml:"description>title-info>movie-title"`
    Authors []Author `xml:"description>title-info>author"`
}

type Author struct {
    Fname string `xml:"first-name"`
    Mname string `xml:"middle-name"`
    Lname string `xml:"last-name"`
}

      

        
        
        
      

    

for fields that I need to work with but don't know how to keep the rest of the file intact. It looks like I need to use xml.decode to select the nodes that I need to change (e.g. http://blog.davidsingleton.org/parsing-huge-xml-files-with-go/ post), skipping unneeded tokens in the xml. encode, but I can't seem to convert this puzzle to some kind of code.