I want to make changes to some of the columns in my query MAIN.
Here is some sample data (all columns are numerical):

ID  | col1  | col2 | cola  | colb
1   |  1    |  17  |   3   |  10
2   |  3    |  6   |   5   |   5

Another query called CHANGES has a list of the required changes (all text columns):

varnm | cndvr| cndvl 
 col1 | col2 | 16,17,18,19   
 cola | colb | 5  

The change I am trying to do – for every row in table CHANGES:
find the columns named in varnm and cndvr – for every row check if the value in the cndvr column exists among the list of values in cndvl, the value in the varnm column remains unchaged. If, on the other hand, the value in the cndvr column does NOT exists among the list of values in cndvl, the value in the varnm column is changed to 9999.
So the expected result in MAIN look like this:

ID  | col1  | col2 | cola  | colb
1   |  1    |  17  | 9999  |  10
2   | 9999  |  6   |   5   |   5

I tried to do it by creating a function called REPFUNC:

(row as record, dt as table) as table =>
    let

        // Extract condition values
        varnm = Record.Field(row, "varnm"), // Column to transform
        cndvr = Record.Field(row, "cndvr"), // Column for condition
        cndvl = Text.Split(T(Record.Field(row, "cndvl")), ","),
    
        // Transform data based on the condition
        TransformedData = Table.ReplaceValue(
                    dt,
                    each varnm, 
                    each if List.Contains(cndvl, Text.From(cndvr)) then varnm else 999999, 
                    Replacer.ReplaceValue, 
                    {varnm}
                )
    in
        TransformedData

I call the function in my MAIN query like this:

let
    Source = ......,
    // Process each row in CHANGES
    ProcessedData = List.Accumulate(
        Table.ToRecords(CHANGES),
        Source,
        (state, currentRow) => Function.Invoke(REPFUNC, {currentRow, state})
    )
in
    ProcessedData

The result: NOTHING CHANGES.
I’ve tried a long list of changes, all resulting in errors. The above code doesn’t throw any errors but as they say – “He who does nothing makes no mistakes”…