Comma Delimited to Rows, Over 255 Records

I have a report that prints four columns of data, with anywhere from a few to a couple hundred records. A comma delimited list of numbers is generated in column D that I need to get into separate rows . Ideally, the numbers from the list in the cell in column D would be parsed(?) and inserted under the original row and into column A, moving all of the records below down a row for each number inserted. Some of these lists have more than 255 numbers. When I use [I]Text to Columns I am warned that data will be lost because there are more records than columns . I need VBA to pull the last record out of the cell (or the first), repeat this with the subsequent records and place in a column. It is the equivalent of selecting the cell, pressing F2, [SHIFT]+[CTRL]+[<--], [CTRL]+[X], [RETURN], [HOME], [ALT]+[I]+[R] (or insert cut record) and [CTRL]+[V]. All subsequent records would be pasted below the prior.

**All cells generated in this report are occupied and the columns are contiguous, A-D. Headings are in row 1 and the entire row is a named range (but the headings alone in A1:D1 are not). After the last record there are two named ranges. The first is a merged cell, spanning columns A and B. The second is also merged, spanning C and D.

Thanks for taking the time.