SD Scheduling Agreements: mass change of payment terms (head & position)

Hello SAP Experts,

due to some changes of our payments terms it is necessary to change also change payment terms in the SD scheduling agreements.

As some customers (of groups of customers) can have some hundred of scheduling agreements I need a tool for mass changes.

(Field VBKD-ZTERM for head and Position)

We tried MASS / MASSD but object type 'BUS2032 Sales orders' do not select scheduling agreement as selection do not include SD document categ. 'E Scheduling agreement'. An object type for scheduling agreements is not shown.

Mass change via VA35 is also not helpful.

Is there a (standard) tool available?

Thank you!

BR Patrick