The application of this term is related to what is referred to in the truncated form of forwarding and more specifically as parcel forwarding or mail forwarding.
Reshipping (service gerund) is basically synonymous with parcel or mail forwarding. Parcel forwarding is a service used to ship a parcel from one location on to another. Mail forwarding refers to shipping paper mail primarily from one location on to another, but it should be understood that this service can also include, in lesser occurrence, the forwarding of parcels as well.
The term, itself, does not identify whether it is a parcel (package) or paper mail that is being shipped again, so to use the term most accurately, it is important to designate this by using the identifying item before or after the term. For example, parcel reship. That way, the object subject to the service is clear.
Also, the term in and of itself does not let us know where it is being reshipped from or where it is being reshipped to. So again, it is important to clarify this by adding a word to identify this either before or after the term. For example, USA to Australia reship.
In summary, reship is a term that means to ship again. It is synonymous with parcel or mail forwarding, which is a service for shipping parcels or mail from one location to that of another. And it is important to indicate from where it is being reshipped and where it is to be received, which is done by adding the pertinent sending location and destination.