After the "second jewish law"(May 5th. 1939), It was impossible for Mr. Stern to obtain the hungarian nationality.
Mr. Stern was stateless:
Czechoslovakia was not existing anymore (his Passport was invalid) and he had no hungarian nationality (couldn't acquire it either).
Mr. Stern ignored the invitation of the foreign police to present himself. Had he done it, he would have been sent to the labor camp.
Mr. Stern forwarded these "invitations" to his lawyer... which gave him 6 months grace.
Mr. Stern tried to work out ways to leave hungary again... only 2 solutions were still possible because of the war: going back to Spain either through Greece or Switzerland.
But then, Mr. Stern received a convocation to go to the labor camp. With this convocation, he went to the Ministry of War. There he was convoked by the Major who spoke perfectly German. Mr. Stern explained that he was just visiting Budapest and that the convocation should be cancelled. The Major advised him to lodge a written request. Mr. Stern went immediately in the next bank office, took a piece of paper and a pen and gave soon after his written request in German to the Major, after which the convocation was reported until 1942.
Some time later, Mr. Stern however found a letter requesting him to report to the barracks. There, a sergeant asked him why he is still in Hungary. He answered that, because of the war, there has been some delay. To which the sergeant replied quite clearly: "Either you leave or you'll be taken".
Another time, he bought a ticket to Greece (with no intention to travel) and showed it to the sergeant...
As another convocation came... he asked his father to write "Departed" on the envelope and returned it, while allowed him to be left in peace.
In the meantime...