Is this a table of items that store data that is looked up into another table such as a line items table that looks up unit prices from a products table?
One method is to add an effective date field in your products table, then specify a sort order in the relationship used by the looked up values fields that sorts related records in descending order by date. That will enable your system to look up info from the related record with the most recent effective date.
If your user wants to enter upcoming changes with a future effective date, you can still get this to work, but you'd need to include a pair of date fields in the relationship such as:
LineItems::ItemNumber = Products::ItemNumber AND
LineITems::DateCreated > Products::EffectiveDate
and still keep the relationship sorted by EffectiveDate in descending order.