I have a tex file with several written chapters. Then I found I need to nest one of them to another. I know this can be done by manually changing the sectioning command one by one but I found it really time consuming and a bit dumb :p
for example, I now have this document
\chapter{big nest}
\section{a}
...
...
\chapter{i want to be a section}
\section{b}
\subsection{c}
I want to nest chapter{i want to be a section} into chapter{big nest} and after compiling, in Table of Contents it should look in a structure like:
\chapter{big nest}
\section{a}
\section{i want to be a section}
\subsection{b}
\subsubsection{c}
Question: Is there a clever way to nest an entire written chapter into another chapter?
By the way, I'm sorry for my poor language and hope you understand my question. I also have tried to search for related topic but I don't know the correct words so I got no related search results. Maybe there is, please let me know. Thank you.