Is it possible to set a field value on a related record? For instance, we have a button to create a PO from a case record. The PO has a field that references the case it was created from. When a PO is created we want a checkbox flagged on the Case record.

with a workflow action (script), yes - or you can have a list/record field on the Case and store the record you create in that record.

OK, thanks for the tip.

If you are making a PO from a case isn't the workflow already running on your case record? If so why can't you just check the box using your current WF?

I think you can also set the newly created case's ID on the original record as part of standard workflow functionality on Create Record workflow action.

@AI1 - I am, however, the checkbox on the case will only get marked once a particular field on the PO has been set.

@mg2017 you can use a different Casen workflow to set that field. use a saved search to identify the Cases that now qualify as being set. Also, can that field just be a Field with a Lookup sourcing to the other record?

Actually, that was my backup plan, to use a saved search and run a scheduled WF, but I wanted to see if it was possible using a single WF.

You can use the subscribe to record action to do what you are describing

Really? I've never used the subscribe to record

Yes you can subscribe to the create PO record then perform transitions or action in the Case WF based on things that happen to the PO record you have subscribed to It's a little tricky to get working but I have done it