Manually change the font-style in content.xml file

I have a document using 2 fonts: [Liberation Sans] and [Liberation Serif]
Is there a way I can manually change the font-style from [Liberation Serif] to [Liberation Serif italic] in content.xml file contained in the ODT file?

I viewed contents.xml file (contained in the ODT file): I have only used 2 fonts (as stated above) and 2 paragraph-stlyes (normal & 2-column), but the context.xml file appears to have 19 paragraph-styles and 27 text-styles.

It may make it impossible to manually make the font-style change.

I maybe just doing some wishful thinking…
Please advise.
Thanks, Tracey
The find/replace utility (font-style-size) is not working correctly in LibreOffice (bug tdf#157743 - I don’t know [if or when] it will be corrected, it seems to have been an issue for a very long time… when writer was being developed by OOo)

Don’t fiddle in contents.xml!

Instead, format your document with styles. If your document is correctly, methodically and consistently formatted with style, you only need to change the leading style.

Unfortunately, I fear you direct formatted a huge part of it. If you come from Word, remember that Word has no notion of character style and any intra-paragraph change must be done manually.

Another reason to have many text styles is change history management. Even if didn’t eanble Track changes, Writer tags your document with technical markup (in “text styles”) in order to ease version comparison.

If you prefer, attach a sample document so that I can have a look at it.

I prefer NOT to fiddle with the contents.
I can only hope that someone will resolve bug tdf#157743
Thanks, Tracey