Please always post complete documents that show the problem. You need to modify a copy of bst file.
\begin{filecontents}{xx.bib}
@inproceedings{x1,
author = {Dave Madengly and Johny Depp},
title = "{Using new Context}",
booktitle = {Proceedings of 1st Conference of the XXX (XXX' 01)},
year = {2001},
crossref = {x2},
pages ="12 -- 20",
}
@proceedings{x2,
editor = {John Doe},
title = {XXX 2001, Proceedings},
booktitle = {Proceedings of 1st Conference of the XXX},
publisher = {The XXXX},
address = {USA},
year = {2001}
}
\end{filecontents}
\documentclass{article}
\begin{document}
\cite{x1}
\bibliographystyle{myplain}
\bibliography{xx}
\end{document}
where myplain.bst
is a copy of plain.bst
with `inproceedings changed to:
FUNCTION {inproceedings}
{ output.bibitem
format.authors "author" output.check
new.block
format.title "title" output.check
new.block
crossref missing$
{ format.in.ed.booktitle "booktitle" output.check
format.bvolume output
format.number.series output
address empty$
{ organization publisher new.sentence.checkb
organization output
publisher output
format.date "year" output.check
}
{ address output.nonnull
format.date "year" output.check
new.sentence
organization output
publisher output
}
if$
format.pages output
}
{ format.incoll.inproc.crossref output.nonnull
format.pages output
}
if$
new.block
note output
fin.entry
}
ie the position of format.pages output
is moved.
\bibliographystyle
command in the LaTeX document. Different styles may make different decisions.