The definitions of support impact are in the Statment of Support.
If a customer submits a ticket via the web ticket form, they can choose the starting priority of the ticket - this is the
Customer Priority field you will see in Zendesk. On ticket creation a trigger sets the main
Priority field (not visible to the customer) to match the
Customer Priority choice. After ticket creation, changes to
Customer Priority do not affect the
Priority field or SLAs.
If a customer emails in a ticket it will get a
Priority of 'Normal' (unless it is sent to the special emergency contact).
Manually setting a ticket's priority in the
Priority field (not
Customer Priority) in Zendesk will change the overall ticket SLA, for both the first and next replies. This allows support to prioritize tickets and update the urgency during the life of the ticket (for example the initial request may be 'High' priority and then follow up questions may need 'Low' priority.) Customers don't receive automatic notifications upon priority change.
Typically, FRT Hawks will set priority during ticket triage as part of the FRT Process in Action. If it comes to pass that a ticket has an incorrect priority, feel free to reset the priority.
There is a Zendesk Macro
General::Changed priority that includes language and links that will be helpful if you need to do this.
Changing the priority in a ticket will change the SLA, because different priorities have shorter or longer SLAs. Please refer to the guidelines and SLA listed in our statement of support.