Whatever your title in this family, you will at some point be the person a customer shouts at while engineering is still diagnosing. Handling that well is a distinct skill and it is heavily assessed in interviews.

• Acknowledge the impact before explaining the cause. People need to hear that you understand what this is costing them before they can hear anything technical.
• Separate what you know from what you suspect, explicitly. Customers forgive not knowing; they do not forgive being told something confidently that turns out to be wrong.
• Give a next update time and hit it, even when the update is that there is no news. Silence is what escalates an incident into a churn risk.
• Do not promise a fix date engineering has not agreed. The pressure to do this is intense and it is how these roles lose credibility internally.
• Be the customer's advocate internally and the company's voice externally, without pretending either side is unreasonable.

Churn is rarely announced. The signals are usage decline, the champion going quiet, a reorganisation on their side, or tickets stopping — which reads as satisfaction and is frequently disengagement. The move is to notice early and get a real conversation, because by the time a renewal is at risk formally, the decision has usually already been made.