Agile has helped the teams to MANAGE changes within the development process. The Agile Manifesto talk about the ‘RESPONDING to change over following a plan’ and the Agile principle says ‘Welcome changing requirements’. The Agile team has to strike a balance between responding to change and working as per the sprint plan. If the change is being REQUESTED by the Product Owner, the team has to decide if they should accept it or not. Some of the deciding FACTORS can be – the volume of change, if the change is too big, the team might ask the Product owner to break it into parts or commit the whole in the next sprint. Second, time of change, if it is inserted early in the sprint, the team consider it rather than in the end. 

Third, if the sprint commitments are getting changed or any new changes are introduced frequently, it should be addressed with the Product Owner.  Whatever might be case, it is a negotiation between the product owner and the development, the team gets to take the final call on the acceptance of change.