Our Jira Service Management SLA response times are currently tied to Priority, and I would like to tie them to Severity instead. Is it possible to edit an existing SLA to make that change, or must I create a new SLA and put it in place of the old SLA? When I click Edit on our SLAs, it isn't possible to change priority to severity; that field is not active.

If it is possible to edit an existing SLA to tie it to Severity instead of Priority, can you tell me how I can make that change? I am a new Jira Admin and am a newbie re doing configurations and making configuration changes.