- Table has a Yes/No field: 'Locked'
- First edit form doesn't need any fields, with a record rule to set 'Locked' to Yes. This page has a redirect rule back to the parent if 'Locked' is already set to Yes.
- Second edit form is the real one with all the fields needed.
Haven't tested any of this of course but there is auto-submit JS code in the developer docs.
And I imagine if you're after record locking then UI changes won't work due to a lack of concurrency (e.g. hiding edit links/buttons if 'Locked' = Yes).
Keen to hear how you go with this Shailendra.