I am trying to write automation rule for SLA breach in JIRA cloud.

[Siri]

I need to write automation rule for SLA breach as SLA is about to expire in 1 day remainder should be sent to assignee through email 

[Mikael Sandberg]

Hi @Siri,

Welcome to Atlassian Community!

If you go to the Automation library (Project settings > Automation > Library) you will see a rule called "When SLA threshold is about to breach → then add comment to notify assignee" that you can use as a template. Just change the threshold and change the comment action to an email one.

[Siri]

SLA threshold breached rule is tracked as bug in jira cloud 

you can refer to JSDCLOUD-10146