How to call a dashboard report from another dashboard report using UMP?
I am not sure I understand what you mean. Are you talking about the dashboard designer? (see below regarding the available widgets):
Add a Dashboard Widget - CA Unified Infrastructure Management - 8.5 - CA Technologies Documentation
Do you want to link to a dashboard from within another dashboard? Or do you want to link to a report? As such there are no dashboard reports.
CA Tech Support
Via the Dashboard portlet, you can drag and drop a circle, rectangle, line, image or text, and configure it as desired and its Widget properties can be configured so that it links to a another Dashboard or a URL. You can choose to link it to an existing dashboard, or set and configure a given URL.
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