Complete a simple WordPress Plugin

Hi. We need to get a wordpress plugin completed by adding an extra function in it. The requirements are as follows: 1. The plugin is a appointment booking plugin between teachers and students and is already built. 2. We need to add a function in which when the student books an appointment with the teacher, the teacher should be able to approve the appointment in order for the student to get the confirmation via email that the appointment is confirmed. 3. Right now when student books an appointment, the teacher is able to approve the appointment but when the teacher books an appointment the student does not get the option to approve. NOTE: The plugin has been developed with ajax, php and jquery. This is a very simple function which we need and the max budget for this job is 1500 INR. If you do this well then we have a lot of big projects for you waiting and can discuss some projects as soon as you finish this one. Thanks and happy bidding!