how to convert an .odt file (writer) in an .odp file (impress)?

[pla]

I would like to convert an .odt file (writer) in an .odp file (impress), how can I do this in libreoffice?
manythanks, ciao :-), Pla

[Hrbrgr]

Look, please, if that helps here.

[mikekaganski]

I’d say, the only way using built-in features without macros would be

soffice --convert-to pdf --outdir my/outdir path/to/file.odt
soffice --infilter="impress_pdf_import" --convert-to odp --outdir my/outdir my/outdir/file.pdf