Turn one row into multiple rows in Excel

I have multiple items that are available in multiple distribution centers (i.e., a many-to-many relationship). There is currently one row per item, with one column for each distribution center. A cell in the row for item X and the column for distribution center Y is marked with the code for distribution center Y if item X is available there and blank otherwise. An item with multiple distribution centers will have multiple distribution center codes (in their respective columns). So the current sheet looks like:

    |   A    |         B         |*|                      S-AJ                      |
1   |  ID #  |   Description     |…|              Distribution Centers              |
2   |   17   |   Ginkgo Biloba   |…|      |      |      |      |      |      |  SE  |
3   |   42   |   Ginseng         |…|      |  MP  |  MS  |      |  NW  |      |      |
                     ︙

Columns C through R contain other attributes of the items, such as UPC code, cost, and price, which are not relevant to this question. My actual sheet has 18 distribution centers, spanning columns S through AJ; I reduced that to get the example to fit into Stack Exchange’s window.

I need to have a single distribution center column, with a single distribution code per row, and then duplicate the rows as needed for items that currently contain multiple codes. The result should look like:

    |   A    |         B         |*|   S  |
1   |  ID #  |   Description     |…|  DC  |
2   |   17   |   Ginkgo Biloba   |…|  SE  |
3   |   42   |   Ginseng         |…|  MP  |
4   |   42   |   Ginseng         |…|  MS  |
5   |   42   |   Ginseng         |…|  NW  |
                     ︙

where cells A3:R3, A4:R4, and A5:R5, contain the same information.

The only way I can think of doing this, which would be time consuming, would be to copy the item number into multiple rows; and in the column that has the distribution code I would change code for the item that is available in each distribution center. I will be doing this for 900 items. Is there an easier way to do this?