Hedda pretends to be the desk manager and calls steve to trick him into giving her his password. what social engineering attack has hedda performed?

The answer is "impersonation".

Impersonation is when a person assumes the role of somebody you are probably going to trust or obey convincingly enough to trick you into enabling access to your office, to data, or to your data frameworks. This sort of social engineering plays on our common propensities to trust that individuals are who they say they are, and to take after guidelines when asked by a specialist figure. It includes the conscious manipulation of a casualty to acquire data without the individual understanding that a security rupture is happening.