let
    Источник = Excel.CurrentWorkbook(){[Name="Таблица1"]}[Content],
    #"Измененный тип" = Table.TransformColumnTypes(Источник,{{"Столбец1", type text}, {"Столбец2", Int64.Type}}),
    #"Replaced Value" = Table.ReplaceValue(
        #"Измененный тип", 
        each [Столбец1],
        7,
        (a,b,c) as number => if b="q" or b = "w" then c else a,
        {"Столбец2"})
in
    #"Replaced Value"

let
  src = Table.Buffer ( Excel.CurrentWorkbook(){[ Name = "data" ]}[Content] ),
  typed = Table.TransformColumnTypes ( src, { { "Столбец2", Int64.Type } } ),
  tbl = Table.Repeat ( typed, 10000 ),
  replace = Table.FromRecords (
    Table.TransformRows (
      tbl,
      ( r ) =>
        Record.TransformFields (
          r,
          {
            { "Столбец2", each if r[Столбец1] = "q" or r[Столбец1] = "w" then 7 else _ },
            { "Столбец1", ( x ) => if x = "q" or r[Столбец2] = 5 then x & "!!!" else x }
          }
        )
    ),
    Value.Type ( tbl )
  )
in
  replace