1. Call the customer and explain him that, this will not be possible. Provide him with statistics and clearly communicate that Wipro may even terminate the contract
2. Analyze the extra effort involved and give a separate proposal for incorporating the additional functionality. Increase the cost so that the customer thinks twice, before changing his requirements again.
3. Accept the situation as is and determine the impact of the changes. Quantify the impact in terms of features, effort, schedule and resources (manpower). Negotiate with the customer with data on hand and reduce the discomfort due to the changes and strike a new balance.
4. Accept the changes without any hesitations to impress the customer.
5. Any other option.