I'd like to have users be able to run a report from a URL but be able to pass a parameter to that report via the URL.
from a URL
How?
And no, a macro won't work.
I would to suggest to test the Rest Api commands, maybe this can fit your purpose. Check out this splunk answers-> https://answers.splunk.com/answers/438244/rest-api-to-re-trigger-report-using-saved-search-w.html
For further information on Splunk Rest Api's check this document -> https://docs.splunk.com/Documentation/Splunk/7.3.2/RESTREF/RESTprolog
