The application for new passport can be submitted at anytime, even if the previous one is still valid.
When applying for a new passport, the previous, still valid passport must be presented to the authority in charge. The previous passport will be invalidated when applying for a new passport, however, upon request, it can be returned for travel until the new document is issued; in the case of the latter the new passport can only be collected in person, in order to invalidate the old one which must be presented at the collection of the new document.
The used or expired emergency travel documents must be submitted at the Consular Office.
If you cannot present your still valid passport, you must give your written statement at the consulate about its whereabouts (stolen, lost or damaged).