Due to risk profiles under NEC Main Options, can PPN guidance be applied against Options A & B in terms of Advanced Payment mechanism for Work Not Done To Date if included in the accepted programme?
Assuming you are talking about PPN02/20 which deals with supplier relief you would most likely need to use a legal device such as a deed of amendment or variation to introduce the recommended measures.
You could introduce secondary Option X14 in this way however if your contract is already in progress then the standard clauses would need to be amended. You could amend the contractual payment periods so instead of the standard 21 / 28 day regime they are reduced to 7 days or even payment being due on submission of an invoice. You could also provide payment for materials on site, in Option B this would need the standard clauses amending however in Option A it may only be the Activity Schedule that requires amending.
Be aware that these measures aren’t intended to be applied carte blanche and contractors need to be prepared to operate on an open book basis (even in Option A and B ECCs) so that the employer can establish that the contractor needs the relief, can ensure the contractor isn’t using this as a profit making venture, and also can monitor that the contractor is actually passing the relief onto their supply chain.