如何改变标题的大小？

Question

我需要更改“摘要”的大小，只有标题必须影响内容必须保持不变，我想要一个 20 号字母大小

\documentclass[11pt,letterpaper]{report}    
%\usepackage{etoolbox}
\usepackage{titlesec}

\begin{document}


\begin{abstract}
El principal mecanthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis intro
\end{abstract}
\section{Exp}
this Exp SECTION
\tableofcontents
\chapter{ETAPA2}
\label{cap:experimental}
this intro

\section{Exp2}
this Exp SECTION

\end{document}

Answer 1

\documentclass{report}

\usepackage{lmodern,lipsum}

\renewcommand{\abstractname}{%
  \fontsize{20}{24}\selectfont\bfseries SECCI\'ON RESUMEN}

\begin{document}

\begin{abstract}
\lipsum[1]
\end{abstract}

\end{document}