  Protocol specifications often identify the roles involved in communications.
In multiparty protocols that involve task delegation it is often useful to
consider settings in which different sites may act on behalf of a single role.
It is then crucial to control the roles that the different parties are
authorized to represent, including the case in which role authorizations are
determined only at runtime. Building on previous work on conversation types
with flexible role assignment, here we report initial results on a typed
framework for the analysis of multiparty communications with dynamic role
authorization and delegation. In the underlying process model, communication
prefixes are annotated with role authorizations and authorizations can be
passed around. We extend the conversation type system so as to statically
distinguish processes that never incur in authorization errors. The proposed
static discipline guarantees that processes are always authorized to
communicate on behalf of an intended role, also covering the case in which
authorizations are dynamically passed around in messages.
