Liam, you need to join the states table twice:
SELECT m.member, h.HomeState, m.WorkState
FROM master m
LEFT JOIN States h ON h.[ID] = m.HomeState
LEFT JOIN States w ON w.[ID] = m.WorkState
Cheers
ChrisM
For fast, accurate and documented assistance in answering your questions, please read this article.
Understanding and using APPLY, (I) and (II) Paul White
Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden