what is the procedure when a person is charged with aggravated assault endangerment.

Aggravated Assault and Endangerment are two separate crimes. Agg Assault is always a felony and can have varying degress of seriousness depending on many factors such as the age of the victim, whether there was serious physical injury, whether a deadly weapon was used, etc. Endangerment can be charged as a class 6 felony (lowest felony level) or as a class 1 misdmeanor depending on whether it involved substantial risk of imminent death (felony) or just risk of serious injury (misdemeanor). I'm not sure what you mean by "the person didn't press charges".  Someone reported the incident to the police and now the state (prosecutor) is pressing charges.  If the case is in regional court center (RCC) in Maricopa County the prosecutor will make a plea offer right away at the first status conference. It could be a probation offer, it could be probation with jail time, or it could be a prison offer, depending on the facts of the case. For someone with no priors, a prison offer would still be likely if there was a gun involved. If it is a more serious case (i.e., gun involved), the status conference and preliminary hearing will likely be vacated (but she still needs to show up just in case) and your friend would likely be indicted by a grand jury. Your friend would be summoned to appear for arraignment shortly thereafter. A plea offer may not come right away in this case. Keep in mind that the state must prove every element of the assault and endangerment charges beyond a reasonable doubt and should be held to that burden.