converting rests with specified vertical position to common rests

[Arno Rog]

L.S.

In the process of converting an musicXML file (from capella) to lilypond all the
rests are converted to rests with a specifed vertical position.
Is there a way to convert them to 'ordinary' rests without ruining the score
(due to the use of \relative music notation)?
I'd like to stick to using \relative notation.

Thanks in advance.

Arno Rog