If it is just one instance of a chapter, you could implement a solution ad hoc that does everything a normal \chapter does:
- starts a new page at correct side:
\cleardoublepage
- increment chapter counter the proper way (works with
\label): \refstepcounter{chapter}
- add that chapter to Table of Contents:
\addcontentsline{toc}{chapter}{\protect\numberline{\thechapter}<title of chapter here>}
- set page marks:
\chaptermark{<title of chapter here>}
After that, you can just make your title “by hand”. You could copy some of the style of chapter from report class: open report.cls (find its path on .log file) and search for definition of command \@makechapterhead.
I put everything together in the following MWE, making a definition in \customchapter.
\documentclass{report}
\usepackage{ifthen}
% a no numbered custom chapter
\newcommand{\nonumberchapter}[2][]{%
% handle optional short chapter title
\ifthenelse{\equal{#1}{}}%
{\def\customchapterShortTitle{#2}}%
{\def\customchapterShortTitle{#1}}%
% start a new page at correct side
\cleardoublepage
% providing an anchor for hyperref
\csname phantomsection\endcsname
% add chapter to Table of Contents
\addcontentsline{toc}{chapter}{\customchapterShortTitle}%
% set page marks
\chaptermark{\customchapterShortTitle}%
% draw chapter title
{\centering
% \vspace{20pt} % space before Chapter N
\Huge\bfseries #2\par\nobreak
\vspace{40pt}}}
% a custom chapter
\newcommand{\customchapter}[2][]{%
% handle optional short chapter title
\ifthenelse{\equal{#1}{}}%
{\def\customchapterShortTitle{#2}}%
{\def\customchapterShortTitle{#1}}%
% start a new page at correct side
\cleardoublepage
% providing an anchor for hyperref
\csname phantomsection\endcsname
% increment chapter counter the proper way
\refstepcounter{chapter}%
% add chapter to Table of Contents
\addcontentsline{toc}{chapter}{%
\protect\numberline{\thechapter}\customchapterShortTitle}%
% set page marks
\chaptermark{\customchapterShortTitle}%
% draw chapter title
{\centering
% \vspace{20pt} % space before Chapter N
\huge\bfseries Chapter \thechapter\par\nobreak
\vspace{20pt}%
\Huge #2\par\nobreak
\vspace{40pt}}}
\begin{document}
\tableofcontents
\chapter{A normal chapter}
Some text.
\customchapter{A custom chapter}
Some text.
\nonumberchapter{A custom nonumber chapter}
Some text.
\end{document}
Edit: added after not numbered version too.
Edit2: added \phantomsection in order to work with hyperref.
titlesecpackage. It defines atitlespacingand a\titleformatcommands. – Bernard Oct 26 '21 at 16:53