Use One Column in Two Column Format Paper

Question

I am writing a paper on a journals template which uses two column format but some of my tables and pictures doesn't fit in two columns and I need them to be placed in one column. Now, I have used multicol package, but it messes up the template of research journal. I have also used \onecolumn command but it shifts the tables onto next page. So, can someone tell me if there is another way to force one-column tables into two-column format.

\documentclass[Afour,sageh,times]{sagej}
\usepackage{multirow}
\usepackage{moreverb,url}

\usepackage[colorlinks,bookmarksopen,bookmarksnumbered,citecolor=red,urlcolor=red]{hyperref}

\newcommand\BibTeX{{\rmfamily B\kern-.05em \textsc{i\kern-.025em b}\kern-.08em
T\kern-.1667em\lower.7ex\hbox{E}\kern-.125emX}}

\def\volumeyear{2016}

\begin{document}

\runninghead{Smith and Wittkopf}

\title{A demonstration of the \LaTeXe\ class file for
\itshape{SAGE Publications}}

\author{Alistair Smith\affilnum{1} and Hendrik Wittkopf\affilnum{2}}

\affiliation{\affilnum{1}Sunrise Setting Ltd, UK\\
\affilnum{2}SAGE Publications Ltd, UK}

\corrauth{Alistair Smith, Sunrise Setting Ltd
Brixham Laboratory,
Freshwater Quarry,
Brixham, Devon,
TQ5~8BA, UK.}

\email{alistair.smith@sunrise-setting.co.uk}

\begin{abstract}
This paper describes the use of the \LaTeXe\
\textsf{\journalclass} class file for setting papers to be
submitted to a \textit{SAGE Publications} journal.
The template can be downloaded \href{http://www.uk.sagepub.com/repository/binaries/SAGE LaTeX template.zip}{here}.
\end{abstract}

\keywords{Class file, \LaTeXe, \textit{SAGE Publications}}

\maketitle

\section{Introduction}
Many authors submitting to research journals use \LaTeXe\ to
prepare their papers. This paper describes the
\textsf{\journalclass} class file which can be used to convert
articles produced with other \LaTeXe\ class files into the correct
form for submission to \textit{SAGE Publications}.

The \textsf{\journalclass} class file preserves much of the
standard \LaTeXe\ interface so that any document which was
produced using the standard \LaTeXe\ \textsf{article} style can
easily be converted to work with the \textsf{\journalclassshort}
style. However, the width of text and typesize will vary from that
of \textsf{article.cls}; therefore, \textit{line breaks will change}
and it is likely that displayed mathematics and tabular material
will need re-setting.

\begin{table}[h]

  \centering

  \caption{Add caption}

    \begin{tabular}{cclcccccccccc}

    \toprule

          & \textbf{1} & \multicolumn{1}{c}{\textbf{2}} & \textbf{3} & \textbf{4} & \textbf{5} & \textbf{6} & \textbf{7} & \textbf{8} & \textbf{9} & \textbf{10} & \textbf{11} & \textbf{12} \\

    \midrule

    \multirow{4}[4]{*}{\textbf{X}} & \multirow{2}[2]{*}{\textbf{A}} & \textbf{C} & D     & E     & G     & G     & H     & \textbf{I} &       &       &       &  \\

          &       & \textbf{aa} & 1     & 2     & 3     & 4     & 5     & \textbf{6} &       &       &       &  \\

\cmidrule{2-13}          & \multirow{2}[2]{*}{\textbf{B}} & \textbf{D} & A     & X     & V     & S     & E     & T     & Y     & \textbf{E} &       &  \\

          &       & \textbf{bb} & 1     & 3     & 5     & 6     & E     & W     & T     & \textbf{W} &       &  \\

    \midrule

    \multirow{4}[4]{*}{\textbf{Y}} & \multirow{2}[2]{*}{\textbf{C}} & \textbf{aa} & 4     & d     & 5     & 8     & 6     & 7     & \textbf{8} &       &       &  \\

          &       & \textbf{s} & a     & g     & j     & y     & r     & d     & \textbf{s} &       &       &  \\

\cmidrule{2-13}          & \multirow{2}[2]{*}{\textbf{D}} & \textbf{F} & 4     & E     & 5     & R     & T     & 7     & 8     & E     & 10    & \textbf{J} \\

          &       & \textbf{D} & S     & F     & YE    & G     & E     & J     & D     & T     & U     & \textbf{S} \\

    \bottomrule

    \end{tabular}%

  \label{tab:addlabel}%

\end{table}%

In the following sections we describe how to lay out your code to
use \textsf{\journalclass} to reproduce much of the typographical look of
the \textit{SAGE} journal that you wish to submit to. However, this paper is not a guide to
using \LaTeXe\ and we would refer you to any of the many books
available (see, for example, \cite{R1}, \cite{R2} and \cite{R3}).

\section{The three golden rules}
Before we proceed, we would like to stress \textit{three golden
rules} that need to be followed to enable the most efficient use
of your code at the typesetting stage:
\begin{enumerate}
\item[(i)] keep your own macros to an absolute minimum;

\item[(ii)] as \TeX\ is designed to make sensible spacing
decisions by itself, do \textit{not} use explicit horizontal or
vertical spacing commands, except in a few accepted (mostly
mathematical) situations, such as \verb"\," before a
differential~d, or \verb"\quad" to separate an equation from its
qualifier;

\item[(iii)] follow the journal reference style.
\end{enumerate}

\section{Getting started} The \textsf{\journalclassshort} class file should run
on any standard \LaTeXe\ installation. If any of the fonts, style
files or packages it requires are missing from your installation,
they can be found on the \textit{\TeX\ Collection} DVDs or downloaded from
CTAN.

\end{document}

This is small portion of standard template of journal i want the table to be at the center of page under one column configuration & the remaining text (excluding) before & after table to be in two column format

Answer 1

That's what the figure* environment is for.

\documentclass[twocolumn]{article}


\usepackage{lipsum}
\usepackage{graphicx}

\begin{document}
    \lipsum[1-3]
    \begin{figure*}[ht]\centering
    \includegraphics{example-image-a}
    \end{figure*}
    \lipsum
\end{document}