You will need to set up two different screen formats (.FMT files).
 
For example:
Step 1: Create a new screen format that will function as a minimally updateable format (only a few fields can be updated).
 
$ MCR DMS:SCREEN
Data File Name? data filename
Available Formats Prompt: select the format that will be copied
Option Prompt: select "Create" option
New Format Name: name the new screen format
Description Prompt: describe the new screen format
From pages <ALL>: Accept the default
 
Step 2: Using DMS:SCREEN modify the new screen format so that fields are marked as /NOPROMPT that  you don't want users updating.
 
Step 3: Modify the menu options that the users call so that the user is directed to the correct screen format when working with the file.  For example:
 
ITEM OPTION1
    DESCRIPTION "Update all fields"
    MCR COMMAND "DMS:SCOPE datafile/FORMAT=formatname/OPTION=UPDATE
END ITEM OPTION1
 
or
 
ITEM OPTION2
    DESCRIPTION "Update a few fields"
    MCR COMMAND "DMS:SCOPE datafile/FORMAT=formatname/OPTION=UPDATE
END ITEM OPTION2
 

Greg Pinkston