enlargefirstpage.tex

\documentclass[
12pt,
sections,
headheight=30pt,
headinclude,
firstfoot=false,
enlargefirstpage=true,
foldmarks=false,
backaddress=false,
subject=titled,
twoside=semi,
cleardoublepage=current
]{scrletter}
\usepackage{lipsum}
\begin{document}

\begin{letter}{Name}
  \opening{Dear Name,}
  \lipsum
\end{letter}
\setlength\footskip{100pt}
\begin{letter}{Name}
  \opening{Dear Name,}
  \lipsum
\end{letter}

\end{document}

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%%% mode: latex
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