During RFQ creation you have the option to prevent vendors from updating their quotes. If this option has been selected, vendors may only submit their quotes once while the quoting period is open unless given permission by an organisation user.
To allow a vendor to update their quote:
The vendor will be allowed to update their pricing only once for as long as the Allow Quote Updates checkbox is ticked. After the quote has been updated it will become locked again. To disable a vendor from further updating their pricing, simply un-check the permission box beside Allow Quote Updates.