Has anyone been able to add rejection messages to transactions within a workflow? Do I need to do something like this? http://www.netsuiterp.com/2019/04/trigger-client-scripts-before-workflow.html

Hi @reptar NetSuite does not have a native functionality for this. You could definitely use something like you have proposed . Also if interested we have developed a pre built solution that includes exactly what you are looking for. The pop up window with input prompt. https://www.mgbcpro.com/enhanced-workflow-actions