I have a workflow on PO. I want it to move to another stage if the record is updated and saved with a new total amount, but can’t figure out the condition on the transition. Is it even possible to do?

That's a tricky condition, only thing I could think of is the system notes - that's the only place where the changed field values are recorded. You might need to use a saved search of system notes looking for the total amount of field changes and filtered by transaction internal id. In theory it may work, you gotta play with it a bit 🤔

Okey, thanks. Not possible to compare old and new value somehow?

I've done something similar with PO approval by creating a Workflow field and storing the total amount (of when it was approved) Did it this way so we could check the new total was within a threshold before requiring approval again