We have a flag called "triaged" that we set after Product Management has looked at an incoming issue, set or verified the priority, and overall looked that the ticket has necessary information. We'd like that flag to be cleared in the event that the ticket is reopened, in case the priority or other fields need values. However, there are other checkboxes in the same field that need to remain as needed. We're trying to use the JIRA workflow toolbox plugin to perform that change for us, but are having problems coming up with the proper regular expression to use.
We have considered adding an additonal workflow state, but wanted to avoid that if possible, so we don't need to worry about making sure all of the transitions will work skipping that state or not.
[edit: add requirement to keep other checkboxes in same custom field as they were]