Dear … K. Bank,
As discussed krub,
As per checking, we are not able to issue any letter mentioned non-disclosure of internal public holiday or any other factor that effect reputation of the company according to HP Compliance Policy krub
You may consider issue the letter on behalf of HP since SiS already is HP authorized distributor
You CANNOT mention about delay by HP Public holiday, but you CAN slightly mention something not too specific like overall picture like ‘due to Thailand Public Holiday during Chinese New Year, shipment process has been delayed’