Update Payment Terms at the Supplier Site

Summary

We need to update payment terms at tthe supplier site level

Content

Is there a way we can mass update/load payment terms at the supplier site level. We have suppliers with hundreds of sites and we need to update the payment terms on them. Is there a way this can be done via spreadsheet or API, rather than manually touching all of them to update the payment terms. I saw a link to a SOAP API in one of the threads, but the link was no longer working. I am unable to find anything on support which might help us out. Thank you for any assistance you can provide,