UI - Changes cannot be saved (PPR)

Given I am a PPR user
When I start a transaction on PPR Registration and somebody else is also starting a transaction on the same PPR Registration
And the other party completes their change before me
Then on attempt to save draft or finalize transaction I am presented with a message that my changes cannot be saved

Start by locating the PPR Registration save-draft and finalize flows, then reproduce the concurrent transaction scenario described in the issue. Confirm that when another party completes a change first, the user receives a message and neither saving the draft nor finalizing proceeds.

Written by the indexing model from the issue text.