Replacing Word in a column with condition and list

PhilippeMuniesa ,

Try this, 

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("pU9BDoIwEPxK0zOHthLkWsuqm5TWdAshgR59gfh/RYF4MJroniaZmZ2Zvue5kFJMxzO+901wSARNIJ6ynheyzBfS+IikI3pHrMIWAsFT9PHDFzJ/S7JquAqhtljXfod2jv03rCzEuuWowwGImfuYqCPAGqlb7Qz8ZijkRqnZYL15lGYTaLpFDd3Jeoyve9RaeTxfRp7SDQ==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [CompteNum = _t, CompteLib = _t]),
    AccountToModified = {"401", "402"},
    #"Replaced Value" = Table.ReplaceValue(
        Source,
        each [CompteNum],
        //each if Text.Start([CompteNum], 3) = "401" or Text.Start([CompteNum], 3) = "402" then "1" else [CompteNum],
        each if List.Contains(AccountToModified , Text.Start([CompteNum], 3) ) then "PIVOT" else [CompteNum],
        Replacer.ReplaceValue,{"CompteNum"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Replaced Value",{{"CompteNum", type text}})
in
    #"Changed Type"

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