By using an append query, you can change the starting value of an AutoNumber field in a table to a number other than 1.
Microsoft Access always numbers AutoNumber fields beginning with the number 1. If the table has data in it already, the starting value of the autonumber will be higher than the highest value already in the table. You cannot manually edit an AutoNumber field or change its starting value.
In order to force Microsoft Access to number an AutoNumber field with a number you choose, follow these general steps below:
For a new table that contains no records, you can change the starting value of an AutoNumber field that has its NewValues property set to Increment to a number other than 1. For a table that contains records, you can also use this procedure to change the next value assigned in an AutoNumber field to a new number.
When you enter a record in the remaining table, Microsoft Access uses an AutoNumber field value 1 greater than the value you entered in the temporary table.
Note: If you want to compact the database after changing the starting AutoNumber value, make sure to add at least one record to the table first. If you don't, when you compact the database, the AutoNumber value for the next record added will be reset to 1 more than the highest previous value. For example, if there were no records in the table when you reset the starting value, compacting would set the AutoNumber value for the next record added to 1; if there were records in the table when you reset the starting value and the highest previous value was 50, compacting would set the AutoNumber value for the next record added to 51.