process-reset modifies the dynamic execution state of process. It performs a non-local exit from the currently running function, to cause the process's main function to return.
unwind-protect forms will be run.
process-reset causes an asynchronous non-local exit, it is possible that it can occur within an
unwind-protect cleanup form or before data used by an
unwind-protect cleanup form has been initialized. In some cases, not all cleanups within that form will be run.
LispWorks User Guide and Reference Manual - 13 Feb 2015