Can I create an Automation such that if the Issue is note Assigned then noone can change workflow ?

[mkaran7]

I am trying to set up an automation such that if a ticket is unassigned, and someone tries to change the workflow, It should say that "Please assign the ticket First"

[Jack Brickey]

How about this. Change the workflow to have a Condition that requires Assignee before the issue can be transitioned from initial 'new' state to the next state. Limit who can set the assignee and thereby prevent transitions.

[Colin Helke]

I don't think you can stop the workflow and tell the user to assign it but you can add a post function that assigns the issue to who ever transitions it. 

https://confluence.atlassian.com/adminjiracloud/advanced-workflow-configuration-776636620.html