Complex sentence: After being detached from in February 1917, he was ordered to Berlin as Assistant Naval Attache; however, relations were severed with Germany before his arrival and his orders were changed to report to Petrograd, Russia as Naval Attache.
Split into simpler sentences: After being detached from in February 1917, he was ordered to Berlin as Assistant Naval Attache; however, relations were severed with Germany before his arrival. His orders were changed to report to Petrograd, Russia as Naval Attache.