No probelm! It's my pleasure to help out. Here's some additional info...
1. Great. Let me know how the Delete button works for you!
2. Since you're calling the individual records from different tables, let's say the CallReport table and the RMA table, each table has it's own unique RecordID that you can use to call upon a specific record. And to me it seems that it's the RecordID that you are using for your Call Report # and your RMA # (Please correct me if I'm wrong). So your Call Report # is actually the unique identifier for records in the CallReport table - the first Call Report RecordID is 001, the next 002, etc. And your RMA # is actually the unique identifier for your records in the RMA table - so the first RMA # would be say 001, the next 002, etc. Make sense?
Are you requiring that the Call Report # be a unique value on the second screen as well? If you're referencing the Call Report # on the second screen via a dropdown, it doesn't have to be a unique field on the second screen since the properties of the choices you'll select from the dropdown already are set to be a unique value. Can you tell me what the error message says when you get it?
3. Oh I see... yes, I was thinking you meant locking a custom report via our Report Designer. Sorry for the confusion. I would say that the easiest way to prevent someone from saving any changes to an existing Call Record would be to remove the Save and Save & New, Clear/New and Delete buttons from the screen where you currently view existing records. Add a Create New Call Report button that uses the Show Screen in Pop-up action. Then create a new screen (to go along with that Show Screen in Pop-up action) based on the same table - I'm assuming it's the CallRecord table. This is where you'll create new Call Reports, and here have the Save, Save & New, Delete and Clear/New buttons if appropriate. I think it would be a good idea to have those buttons on the New Call Report screen so that way they can delete a record that they're creating right away so long as they keep the pop-up open in case of duplicate or erroneous entry, but to go back afterward to retrieve it for altering or deletion would be impossible.
Or you can create the new pop-up screen and make all the fields on the original screen read only, still removing the appropriate buttons so as not to confuse your users. That could be another solution as well, but you'll still need that additional screen.
Good luck in your efforts. Sounds like you are really rolling up your sleeves and getting your hands dirty! We love that!