The GetLevelConstant sub converts a string, such as "Designer," into the corresponding constant, such as ACLLEVEL_DESIGNER.
Sub Click(Source As Button)
  Dim workspace As New NotesUIWorkspace
  Dim uidoc As NotesUIDocument
  Dim session As New NotesSession
  Dim db As NotesDatabase
  Dim acl As NotesACL
  Dim entry As NotesACLEntry
  Dim levelString As String
  Dim levelConstant As Integer
  Set uidoc = workspace.CurrentDocument
  Set db = session.CurrentDatabase
  Set acl = db.ACL
  levelString = Inputbox$( "What level?" )
  ' function call to convert the string 
  ' into an ACLLEVEL constant
  levelConstant = GetLevelConstant( levelString )
  ' go through all the entries in the ACL
  Set entry = acl.GetFirstEntry
  While Not ( entry Is Nothing )
    ' if the entry has the level that the user chose
    If ( entry.Level = levelConstant ) Then
      ' append the entry's name to the text list
      ' in the People field
      Call uidoc.FieldAppendText _
      ( "People", entry.Name & "; " )
    End If
    Set entry = acl.GetNextEntry( entry )
  Wend
  ' refresh current document so that 
  ' text list displays nicely
  Call uidoc.Refresh
End Sub
Function GetLevelConstant( desiredLevel As String )
  Dim levelConstant As Integer
  Select Case desiredLevel
  Case "Manager":
    levelConstant = ACLLEVEL_MANAGER
  Case "Designer":
    levelConstant = ACLLEVEL_DESIGNER
  Case "Editor":
    levelConstant = ACLLEVEL_EDITOR
  Case "Author":
    levelConstant = ACLLEVEL_AUTHOR
  Case "Reader":
    levelConstant = ACLLEVEL_READER
  Case "No Access":
    levelConstant = ACLLEVEL_NOACCESS
  End Select
  GetLevelConstant = levelConstant
End Function