How to have selection in field A in Table 1 change the value of field B in Table 2

I'm building a simple app to track the checking in and out of items.

I have an "items" table and an "actions" table. These two tables have a one (item) to many (actions) relationship.

I would like selecting an action from the dropdown list in the action field of the action table to automatically update the status field of the related Item record. E.g. if the action-field selection is "return entire item", I would like the item status to be changed to "returned."

Dynamic Form Rules seem to only allow me to change other field in the same form. How do I make changes to field values for records in other tables?

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Paul Easton
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