John, if you have DW Premise AND are familar with MSQQL data manipiulation, below is a way to reset Automatyic Numbering, otherwise your only choice is to create a different numbering group and re-assign it to all dialogs as required.
Here is how you change Automatic numbering in MSSQL:
1. Find out the value of the Automatic NumberingGroup SettingID - this is column setid in table dwsystem.dbo.DWFCSettings - just search the table for name=yourAutoNumberingGroup name and find out corresponding setid
2, Search table dwsystem.dbo.DWSequence for column settingsid=setid found in step1 and change value of column nextNumber for the row.to a desired number
That will reset the next number.