Once you have submitted your applications, I would suggest you hold back on the networking with the school. While keeping in touch with the school’s current students, alumni and admissions committee members might be really beneficial before submitting your application, it can err on the side of annoyance once your application is submitted.
Give the school a chance to reach out to you, and if possible, tell them then. Informing the school during an interview is also a good way to make sure the information is out there, but especially emailing or calling them for the same is not advised.
After submitting your applications, reach out to the school in case you have improved your GMAT score or something significant of those sorts.
Also, did you know about the job switch before submitting the application? a top school admission committee member had reported a few years back that they rejected an applicant, who was more than qualified for their MBA program and was almost accepted, just because they forgot to mention an upcoming promotion. They did so because it showed carelessness. So, decided whether you want to indulge the school with this new information accordingly.