Change Field Size via VB Code (URGENT!)

[JeffSM]

Some one knows what code should I use to change the field size of a table:

I have already this code that localize the exact field,
but I don't know how update the table!

<b>
Set dbField = dbTable.Field(y)
dbField.Size = aFields(x).Lenght
</b>
Thanks in advance!
Jefferson