change adColNullable attribute after collumn creation?

following is code for setting the adColNullable attribute during column creation, but how do you change it AFTER the column is created?

Code:

---

colTemp.Name = "FaxPhone"
colTemp.Type = adVarWChar
colTemp.DefinedSize = 24
colTemp.Attributes = adColNullable

cat.Tables("Employees").Columns.Append colTemp

---

Assumptions:

Table name(s): Oldtbl, NewTbl

1) Build NewTbl with the structure you want
2) Execute: insert into NewTbl select * from OldTbl
3) Execute: Drop OldTbl
4) Execute: select * from NewTBl insert into OldTbl
5) Execute: Drop NewTbl