Renaming the bibliography page using BibTeX

This does not depend on BibTeX, but on the document class. The article class uses the \refname macro (which is defined as References) when typesetting the bibliography heading; the book and report class use \bibname (which is defined as Bibliography). So try to add e.g. the following to your preamble:

\renewcommand{\bibname}{Whatever floats your boat}

EDIT: Special bibliography packages may use a different mechanism.

Just be careful if you are using babel to setup a language. The \captions<lang> command overwrites everything. Rather use the following

\documentclass[afrikaans, english,%... Global language selection
              ]{book}
\usepackage{babel}%.................. Language setup
    \addto{\captionsafrikaans}{\renewcommand{\bibname}{Lys van Verwysings}}
    \addto{\captionsenglish}{\renewcommand{\bibname}{List of References}}

Change bibliography heading

You can change the heading of your bibliography by inserting a ERT element (Insert→TeX) right before the bibliography with the following command: \renewcommand\refname{New References Header} or \renewcommand\bibname{New Bibliography Header}, depending on whether you use an article or a report/book class.

source

I also tried with \renewcommand\bibname{New Bibliography Header} and it didn't work, but with \renewcommand\refname{New References Header} it did work.