Unable to update Customer Card (Salesperson code field)

i have a dataport that takes in 3 field:

1.customer code,
2.old salesperson code,
3.new salesperson code

Its suppose to functions as find the customer code, replace the new salesperson from csv file.

-My csv files have 2 record for testing purposes, all data
(customer code, old salesperson code, new salesperson code )in the csv files are valid data

-My Data Field for dataport as follows:
CustCode
OldSMCode
NewSMCode

-Properties

AutoSave     = <YES>
AutoUpdate = YES
AutoReplace=<No>

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Without using the commit code at the end of my code, it can't modified the necessary records.

Cust.Modify;
COMMIT;

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