New command to turn to italics

Question

I'd like to create a command that will turn all of the text that follows into italics, but something isn't working. Where am I going wrong?

p.s.: I know I could do it differently, but it's important that it's really a command!

\documentclass[a4paper,11pt,draft]{report}
\usepackage[utf8]{inputenc}

\newcommand\Tom{\par\bigskip\noindent\hbox to35mm{Tom\hfil}\hangindent=35mm }
\newcommand\Mary{\par\bigskip\noindent\hbox to35mm{Mary\hfil}\hangindent=35mm }
\newcommand\action{\par\bigskip\noindent\itshape}

\begin{document}

\Tom
Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem
Ipsum is simply dummy text of the printing and typesetting industry.

\action
This is the action line to put into the new text

\Mary
Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem
Ipsum is simply dummy text of the printing and typesetting industry.
    
\end{document}

Answer 1

So long as you always follow the action directive with a blank line, you can do

\newcommand{\action}{} % to avoid overwriting an existing command
\def\action#1\par{\par\bigskip\noindent\textit{#1}\par}

Full example with other fixes:

\documentclass[a4paper,11pt,draft]{report}

\newcommand\Tom{\par\bigskip\noindent\makebox[35mm][l]{Tom}\hangindent=35mm }
\newcommand\Mary{\par\bigskip\noindent\makebox[35mm][l]{Mary}\hangindent=35mm }
\newcommand\action{}
\def\action#1\par{\par\bigskip\noindent\textit{#1}\par}

\begin{document}

\Tom
Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem
Ipsum is simply dummy text of the printing and typesetting industry.

\action
This is the action line to put into the new text

\Mary
Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem
Ipsum is simply dummy text of the printing and typesetting industry.
    
\end{document}

Alternative, but \action<text> must be followed either by a blank line or one among \Tom or \Mary.

\documentclass[a4paper,11pt,draft]{report}

\newcommand\Tom{%
  \par\bigskip\noindent\makebox[35mm][l]{Tom}\hangindent=35mm
}
\newcommand\Mary{%
  \par\bigskip\noindent\makebox[35mm][l]{Mary}\hangindent=35mm
}
\makeatletter
\newcommand\action{%
  \begingroup
  \par\bigskip\noindent\itshape
  \def\par{\endgroup\@@par}%
}
\makeatother

\begin{document}

\Tom
Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem
Ipsum is simply dummy text of the printing and typesetting industry.

\action
This is the action line to put into the new text
\Mary
Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem
Ipsum is simply dummy text of the printing and typesetting industry.
    
\end{document}