Access denied: PurchFormLetter_PackingSlip

Dear Experts - I received error  "Access denied: PurchFormLetter_PackingSlip" for Correct and Cancel Menu items. I assign Purchasing Agent Role to user and by default this role doesn't contain the menu items Correct and Cancel for received Purchase Orders.  I set the privileges from AOT\Security\Privileges\VendPackingSlipJournalView  PURCHFORMLETTER_PACKINGSLIPCANCEL(access level: Update), PURCHFORMLETTER_PACKINGSLIPCORRECTION(access level: Update).

Thanks,

Faqru Shaik