Ok, so, in effect, we could launch a simple form with a button on it, and
when pressed, it would process a given set of records..and runt he code for
each record.

a typical update in code looks like:

dim strSql        as string

strSql = "update tblCustomers set City = 'New York'" & _
        " where city = 'N.Y.'"

currentdb.Execute strSql

So, the above would look for all records that are "N.Y.", and update them to
the full name of "New York"

So, typical the processing of data is done with sql. You can like build a
query that joins together the two tables you need, and use a single update
as above (your ability to do this is going depend on your sql skills).

Another approach (one we might have to use) is to use a reocrdset, and that
allows us to process each record by record.

Sub MyProcess()

  Dim rstParent        As DAO.Recordset
  Dim strSql           As String
  Dim lngID            As Long

  strSql = "select * from tblMain where active = true"

  Set rstpartent = CurrentDb.OpenRecordset(strSql)

  Do While rstParent.EOF = False

     rstParent.Edit
     rstParent!Active = False
     rstParent.Update

     rstParent.MoveNext

  Loop

  rstParent.Close

End Sub

The above processing loop would take each record, and set the "active" field
to false.

The above is not the best example since we could use a single sql update
statement such as

currentdb.execute "update tblMain set active = false where active = true"

So, using sql update statements is preferred.

In your example, it seems we have a set of "main" records, and for each main
record, we need to execute a update on the child records. Hence, we could
use something like:

Sub MyProcess()

  Dim rstParent        As DAO.Recordset

  Dim strSql           As String
  Dim lngID            As Long

  strSql = "select * from tblMain where active = true"

  Set rstpartent = CurrentDb.OpenRecordset(strSql)

  Do While rstParent.EOF = False

     strSql = "update tblChild set somefield = somevalue " & _
              " where main_id = " & rstParent!ID
     CurrentDb.Execute strSql

     rstParent.MoveNext

  Loop

End Sub

so, you don't actualy "call" the after update code, but simply "reproduce"
the same code in the above loop to update the records in the manner in which
you need.

As a general rule, data processing code does not run, or use forms "after
update" event code. So, simply lay out the logic, and how the update is
supposed to work, and then write code as a above....

That is why I said it better to leave out the forms mumbo jumbo,a nd simple
state the problem:

   eg:

       for each active record in a main table, I need to update some
relented records in a child table.

Now, not being a mind reader, I don't know how you plan to select those
records that need updating..but the above gives the general idea....

If you are new to running update code, MAKE SURE you ALWAYS ALWAYS ALWAYS
make a backup..as this type of code can trash and "run over" data in a table
in a flash!!

So, in effect, the idea is not to run the after udpate code over and over,
but layout the problem at hand, and then write the code to solve that
problem...