Workflow Conditions allow you to check if a transition should be performed by the user. For further information about conditions, click here.
These conditions may be used to:
allow only the reporter to execute a transition.
allow only users with certain permission to execute a transition.
allow the execution to be performed only if code has, or has not, been committed against this issue.
Conditions offered by the SLA PowerBox plugin:
Select the SLA Metric for which a condition will be created.
Choose Yes or No so the condition will check if an SLA Metric is breached / not breached.
Click the Add button to confirm.

Select SLA Metric for which a condition will be created and an SLA Metric State.
Tick the checkbox if you want the condition to be reversed (e.g. 'active' to 'not active' or 'finished' to 'not finished').
Click the Add button to confirm.

Select the SLA Metric for which a condition will be created.
Select Used time or Remaining time, operator, and enter the value.
Click the Add button to confirm.

Pick a Calendar.
Specify how much time of day should remain to count it as a working day.
Select the Start date from which app will count time (can be the custom field).
Check the box if you want a condition to be reversed.
Click the Add button to confirm.

Pick a Metric.
Specify how much time of day should remain to count it as a working day.
Select the start date from which app will count time (can be the custom field).
Check the box if you want a condition to be reversed.
Click the Add button to confirm.

Adding an SLA condition to a transition:
Log in as a user with the 'Jira Administrators' global permission.
Navigate to Admin menu → Issues. Select Workflows to open the Workflows page, which displays all of the workflows in your system.
Click Edit for the workflow that has the transition, you wish to change.
Select the transition from the Transitions (id) section.

Click Conditions in the properties panel.

Click the Add condition option.
Select the needed condition from the list.
Click the Add button to add the condition to your transition.