@EAugum -
Here’s how I would do it.
Rather than bother with changing linked-record fields to indicate device availability, I’d add a few fields to my device record. Now, whenever you are configuring a new [Project], you select the plus sign in the {Device} field and select a record from the list of devices. The first field in the [Equipment] record indicates whether the device is available or not; if the user selects an unavailable device, an alert appears in the linked record, and (if your plan supports record colors), the affected [Project] and [Equipment] records are tagged red.
Within the [Equipment] table, each device record may be linked to multiple [Project] records; only one linked [Project] may be active at any given time. Through the use of interlocking rollups, the date and name of the most recent project with which that device was associated are displayed.
With this approach, devices are automatically tagged as available on the day following the date the most recent project concluded. No middleware or manual toggling of active/inactive devices is required.
Note: Renamed post from “Move record from one field to another” to “Automatically mark resource as available upon end of project” to aid future searchers of the ‘Ask the Community’ forum.
