1. According to customer description, whether it is a new deliverable which is not part of scope baseline or change in specification of deliverable, you need to analyse whether is is possible to produce/implement that deliverable/change and with what additional cost/schedule . Report the analysis to project sponsor to seek permission whether customer demand can be responded with this additional cost and schedule estimate. As per sponsor decision, customer can be intimated.
This is purely a strategic decision by project approving authority.