Duplicate rows based on billing frequency

Hello, Shaiksamar2244 

let
    Source = your_table,
    f_rec = 
        [Monthly = (x) => Date.AddMonths(x, 1),
        Quarterly = (x) => Date.AddQuarters(x, 1),
        Annual = (x) => Date.AddYears(x, 1),
        #"Semi-Annual" = (x) => Date.AddQuarters(x, 2)],
    f = (r as record) as list =>
        [fx = Record.Field(f_rec, r[Billing Frequency]),
        b = List.Generate(
                () => r[Bill Date],
                (x) => x <= r[Term End Date],
                (x) => fx(x)
        )][b],
    tbl = Table.AddColumn(Source, "lst", f),
    expand = Table.ExpandListColumn(tbl, "lst"),
    remove_old = Table.RemoveColumns(expand,{"Bill Date"}),
    rename = Table.RenameColumns(remove_old,{{"lst", "Bill Date"}})
in
    rename

Shaiksamar2244 don't worry. Refresh a query or select some step in the middle and select final step again. Error should go away in PQ editor. I hope so.