DAX - Need next row value

JusticeBaird  this is not an analysis level task, rather it is a data level task which can be resolved by using PQ in the following way

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WckpNV3BKzFHSUYIgQwMDA6VYnWglIwMjQ10DIDIBijol5mUDKV2gLJCyhCpB12uKotcQpB0o6qgfANJqCtZqAqJiYwE=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Date = _t, Account = _t, Amount = _t, Balance = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Date", type text}, {"Account", type text}, {"Amount", Int64.Type}, {"Balance", Int64.Type}}),
    #"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 0, 1, Int64.Type),
    #"Added Custom" = Table.AddColumn(#"Added Index", "newAccount", each let x = #"Added Index"[Account],
    y = #"Added Index"[Date],
    z = if [Date]="Beg Bal" then x{[Index]+1} else [Account]

    in z),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Index"})
in
    #"Removed Columns"