Data Load to Update Parent Account

Summary

I am trying to do data load to update the Parent Account.

Content

Initially I tried for 1 account and it's uploaded. After that I tried to load using the same mapping and data load process completed successfully but it's not reflecting in the system. When I check for the accounts, Parent Account details are not populated.

Not sure what was the issue. I am using the same mapping which used for first record but still it's not reflecting in the system. Below is the attribute used for data load,

PartyNumber,ParentAccountPartyNumber