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He/she may be used to refer to an object. The accepted practice in English is for boats and ships to be considered female; this is unusual enough to be remarked upon by non-sailors.

All other uses that I am aware of are casual anthropomorphisms rather than formal. A vehicle is often referred to as female by the owner or a mechanic. A favorite tool or instrument may be gendered. In all of these cases, the gendering is specific to that object, not the entire class, and indicates emotional involvement. It is often inconsistently applied, but I am not aware of an object which is considered to switch genders, only to gain or lose a specific gender in the course of conversation.