This is handled on the Rental Quote Plan (CQP).

Or one can manually create a price a price agreement (PRA) when the order is created.

Each order you make will have its own price agreement (PRA) which is a copy of the price template (PRT),

and this can be changed as required.

If the user creates a Rental Quote Plan (CQP), the price will be taken from here instead of from the price template (PRT).

More about Rental Quote Plans (CQP ) can be found here:

Add article and customer specific price (CQP)