endorsement policy

An insurance endorsement is an amendment or addition to an existing insurance contract which changes the terms or scope of the original policy. Endorsements may also be referred to as riders. An insurance endorsement may be used to add, delete, exclude or otherwise alter coverage. An insurance endorsement may be issued mid-term, at the time of purchase, or at renewal. The insurance endorsement is a legally binding amendment to the insurance contract. 

So, the taxability or its exemption remains same as per original condition of premium paid to sum assured.