Once you add a record to a local DB, I don’t think you can delete it via blocks. You might want to save the items to an actual list and then save the list under local storage. Then you can remove an item from one list and add it to another and then save both lists.
How do I actually do this though? I am basically creating a ‘favourites’ list. They select items from one list and it is added to another. Lots of of the advice on the web relates to App Inventor. This had a ‘add items to list’ option, which I cannot see in x-thunkable.