Foiled assassination attempt on President-elect Franklin D. Roosevelt

The transcript describes a witness's account of an attempted shooting incident. The witness realized the shooter was targeting someone and intervened by pushing the pistol upwards to prevent harm. There was confusion about the shooter's target, with mentions of the President, Boston, and the Mayor of Chicago.

What did the witness try to do to prevent harm during the incident?

Who was the intended target of the shooting according to the witness?