Modules & VBA :: Arguments - How To Pass From Private Sub To Function

I have a after update event that will match the written record with any exist record in a table in the field "OrgName". If it doesn't find exact match, will call a function with a "soundex" algorithm to see if there is only a misspelling or another name altogether.

In the afterupdate event, I have a string called strOrg (wich is the name I want to compare).

I have the soundex function in a module, so I can use it for several form generally.

What I want is to pass the strOrg to the soundex function, however I don't know how to declare the variables. however I keep having this error:

"compile error: Argument not optional"

and goes to the line tagged as 1 in the private sub afterupdate

The afterupdate sub is the following:

Code:

Private Sub tOrgName_AfterUpdate()
Dim strOrg As String
strOrg = Me.tOrgName.value
If IsNull(DLookup("orgID", "torg", "OrgName = '" & strOrg & "'")) Then
resMsg = MsgBox("This organization name is not in the list. If you want to look for similar names press YES, if you want to register a new organization press NO.", vbYesNoCancel, "Organization not found")

[Code] ....

and the soundex function is declared as

Code:
Public Function Soundex(strOrg As String) As String
Dim Result As String, c As String * 1
Dim Location As Integer