Want to update parent lookup list from child based on lookup selection/deselection

Question

I have two sharepoint lists, Asset Detail (parent) and Asset Assignment (child) list. on Asset Assignment I have a field where I select multiple Asset items, so at the asset assignment side, I can assign multiple assets items to a record.

Now my requirement is once a item from parent list has been used in child, that item shouldn't be available in the lookup to select. Understand the scenario like there is one single asset which can assign to someone, if that asset has been assigned then it shouldn't be available in the lookup for further use or assignment.

I have implemented the scenario where on parent list I've created a column called status, which specify whether current item is Assigned or Ideal. but I stuck with the update part, how can I update the parent list every time child item created and modified with the assignment lookup. so if I remove an item in lookup from asset assignment, then it should update the corresponding item in parent list as ideal, or in case of assignment it should update the parent item field as Assigned.

Any solution which I can use, I tried flow but stuck with the update part how should be the logic. other alternative could be powerapp.

Answer 1

There is a action called update item in Flow. Set the trigger to be when an item is created or modified. Then update the item with the id of item in lookup column. For removing item in assest assignment, you can create another flow which is triggered by when an item is deleted.