Hi,
Are you asking for the change in valuation type configuration or the change in material master valuation type - at master data level? In your question, I could see "change history for Valuation Type master Data."
If it is at master data level, then check in MM06 whether the valuation type has been marked for deletion for the material.
If you want change logs, go to AUT10 transaction , press F9 and then insert table MBEW, change doc object as "Material", object value as the material number (if you know) as shown below, along with date and execute.
If you are asking for customizing change, there should be a TR for the same and you will be able to track as Mr. Jurgen already explained.
Regards,
AKPT