Beware that if you have ANY relationships at all using the source table, if you actually change that table, you kill the relationships.
This thing you want to do is a flat-file concept in a relational world. For a really short table, it makes sense. If the table has more than 255 records, though, you are screwed supremely because the resulting "flipped" table will require more fields than Access allows.
There is also the issue that the keys in this table suddenly make no sense either, even if no external relationships exist.
STRONGLY recommend rethinking the requirement to look for normalization and other "gotcha" items. If this is a one-time change, OK. If this is a commonly repeated event, your concept is going to eat your socks very quickly. Access might not be the tool for you. In that case, look hard at doing this entirely via Excel.