How remove margin in a paragraph that continues in two pages with different margin?

Question

I've created a document whose margins have different odd and even pages. I want to write a paragraph with no margin in two pages runs. If I use the command \newgeometry new paragraph starts at the top of new page, that I want to start at the same place. And the command \begin{adjustwidth}{}{} such marginalized different odd and even pages are not useful. Please guide me in this regard.

I use this command for create margin:

\documentclass[11pt,fleqn]{book} 
‎‎\usepackage[total={215mm,285mm}‎,‎top=3cm,bottom=3cm,headsep=10pt,
    vmargin=2cm,
    outermargin=7cm,
    innermargin=2.5cm,
    marginparwidth=5cm,
    marginparsep=10pt]{geometry}

Answer 1

I did not understand the question, but here is one way to change the horizontal margins of one (or several) paragraphs midtext.

Please be aware, that the paper has to be bigger than the type block.

\documentclass[11pt,fleqn]{book} 
\usepackage{scrextend}
\usepackage{blindtext}
\usepackage[
    paperwidth=260mm,%%The paper must be bigger than the body
    paperheight=330mm,
total={215mm,285mm},
%top=3cm,
%bottom=3cm,
%%headsep=10pt,
%%%vmargin=2cm,
%outermargin=7cm,
showframe,
%innermargin=2.5cm,
%marginparwidth=5cm,
%marginparsep=10pt
]{geometry}
\begin{document}
\blindtext

\begin{addmargin}{-1cm}
    \blindtext
\end{addmargin}

\begin{addmargin}[2cm]{-1cm}
    \blindtext
\end{addmargin}
\clearpage
\blindtext

\begin{addmargin}{-1cm}
    \blindtext
\end{addmargin}

\begin{addmargin*}[2cm]{-1cm}
    \blindtext

    \blindtext
\end{addmargin*}
\end{document}