Dim rst As Recordset
Set rst = CurrentDB.OpenRecordset("<table name>", dbOpenDynaset)
rst.AddNew
rst!<field> = Me.<field>
...<same for all fields to update>
rst.Update
<repeat above code for each subform's source>
Me.Requery
I'm not sure which library allows for recordset operation. I think it's Microsoft Visual Basic for Applications Extensibility 5.3 (something like that). It could be MS Access 9.0 Object Library or MS DAO 3.6 Object Library.
As you can see, the basic idea is to update the source table(s), then requery to update the form. In case this causes the form to go to the first/last record rather than stay at the current record, you can use a bookmark object:
Dim bmk As Bookmark
(before performing above recordset operations)
bmk = Me.Bookmark
(after requerying)
Me.Bookmark = bmk