This is referring to the Weimar government before Hitler rose to power- how much power did the original constitution give to each?
Apparently, the President of the Weimar Republic had powers like the President has in many countries, and more power added into his commitment within emergency state (Article 48 of the Weimar Republic Constitution).
The Reich Chancellor was one of the highest in the Government, which could replace the Reich President (Article 51).
Edit: There was also a Reichstag arson (according to https://en.wikipedia.org/wiki/Reichstag_fire and its references). No matter the arsonist was a Communist or just a fool (and so "flagged" as Communist), it helped to justify the request for an emergency decree and, possibly, mass arrests of communists (including Reichstag members). It may enabled Hitler's party to form a Reichstag majority.