How to update a custom function in Power Query

Hello,

I watched a youtube vid for consolidating worksheets from multiple workbooks and it worked well. I started by creating a query for just one sheet from one workbook and using that to create a custom function and then a 2nd query to call all of the workbooks and invoking the custom function.

Once completed, I realized that I should have removed rows from the bottom in the original query, which was easy enough. But the custom function did not automatically update and I cannot find anywhere to do so. Please tell me I do not need to start over from scratch and I'm simply overlooking something.

theory: try in original query Table.RemoveLastN(Source,5) (where 5 is a last five rows) then Refresh you result
or post any example with your M and describe what you want to achieve

My original question relates to the Fn step highlighted in red on the attached screenshot. When I make a change to the original query "hFn Genrl Input" the Fn did not automatically update. Would Append Query be the appropriate next step?

I also now have a secondary question. I am failing at the Fn creating tables because the worksheets in question have 1 column that does not stay consistent. It contains the monthly date on an individual level for which I tried changing the column heading prior to running the function. Internet searches suggested an IF/THEN statement but I am not sure how to do that within the query. I know that the simplest fix would be to change the column in the workbooks, however I am trying to avoid modifying the workbooks.

sorry but I am not a "graphic man",
post an excel example file