Here’s what the RFC says. (the doubt I have is that according to this RFC we can never delete a previous name, just create a new version).
NRS data on the network, is by its very nature, public. Which means that it cannot be deleted. This concept forms the basis of the Perpetual Web, where data can only be appended to (using AppendOnlyData). As a consequence RDF data described here is a type of ‘versioned’ data, with the
keyof an AOD being aUTC timestamp, and thevalueof an entry being a string representation of the RDF data. This means that all versions of the data can be accessed (via version?v=222url params, see xorurl rfc for more info, as well as the order of this data, and the timestamp changes were made. (Although these timestamps are applied client side, and therefore are optional so should not be treated with any reverence.)