I wish to have comment 1, comment 2 as running numbers, and for each reviewer I want to restart the running number, is there a good way to achieve this? Following is how the pdf currently looks, and its latex (you can see that I hard code the number in the latex).

 \documentclass{article}
\usepackage[usenames]{color}

\begin{document}
\setlength{\parindent}{0pt}
\setlength{\parskip}{2ex}

\title{Change Summary}

\author{This is author}

\maketitle

We are thankful for the valuable and insightful comments from referees.
These comments have helped us to improve our work.
We have fixed the typos and language problems based on the reviews.

\section*{Reviewer 1}
\textbf{Comment 1}:
This is comment 1

.

\textbf{Comment 2}: This is comment 2

\section*{Reviewer 2}
\textbf{Comment 1}: This is comment 1

\end{document}

-

With several counters a solution reads

\documentclass{article}
\makeatletter
\newcounter{reviewer}\setcounter{reviewer}{0}
\newcounter{comment}\setcounter{comment}{0}
\def\reviewer{\stepcounter{reviewer}\section*{Reviewer \arabic{reviewer}}}
\def\comment{\stepcounter{comment}\textbf{Comment \arabic{comment}:}}
\begin{document}
\setlength{\parindent}{0pt}
\title{Change Summary}
\author{This is author}
\maketitle
We are thankful for the valuable and insightful comments from referees.
These comments have helped us to improve our work.
We have fixed the typos and language problems based on the reviews.
\reviewer
\comment\ This is comment 1

\comment\ This is comment 2

\reviewer
\comment\ This is comment 1

\end{document}


-

I improved the solution, with just one counter

\documentclass{article}
\usepackage{tocloft}
\usepackage[usenames]{color}

}

\begin{document}

\setlength{\parindent}{0pt}
\setlength{\parskip}{2ex}

\title{Change Summary}

\author{This is author}

\maketitle

We are thankful for the valuable and insightful comments from referees.
These comments have helped us to improve our work.
We have fixed the typos and language problems based on the reviews.

\section*{Reviewer 1}

\section*{Reviewer 2}

\end{document}


Quick and dirty solution:

\documentclass{article}

\usepackage[usenames]{color}

}

\begin{document}
\setlength{\parindent}{0pt}
\setlength{\parskip}{2ex}

\title{Change Summary}

\author{This is author}

\maketitle

We are thankful for the valuable and insightful comments from referees.
These comments have helped us to improve our work.
We have fixed the typos and language problems based on the reviews.

\section*{Reviewer 1}

\section*{Reviewer 2}

\end{document}


-

You create a counter "within" a counter. chngectr might be just the trick here. It is worth looking at.

\newcounter{reviewer} %create new counter reviewer

\counterwithin{comment}{reviewer} % create comment witnin reviewer

-

Here you can also add labels for \ref:

\documentclass{article}

\newcounter{reviewer}
\newcounter{comment}[reviewer] % comment is reset when reviewer is stepped
\makeatletter
\renewcommand\p@comment{\thereviewer.}
\makeatother

\newcommand{\reviewer}{%
\refstepcounter{reviewer}%
\section*{Reviewer \thereviewer}
}
\newcommand{\comment}{%
\refstepcounter{comment}%
\textbf{Comment \thecomment:}\enspace\ignorespaces
}
}

\begin{document}

\title{Change Summary}

\author{This is author}

\maketitle

We are thankful for the valuable and insightful comments from referees.
These comments have helped us to improve our work.
We have fixed the typos and language problems based on the reviews.

\reviewer
\comment
This is comment 1

\comment\label{rev1-comm2}
This is comment 2

\reviewer
\comment
This is comment 1


\renewcommand\p@comment{Reviewer~\thereviewer, Comment~}