Kafka how to reset number of partitions in a topics

I wanted to figure out how to reset number of partitions in my topic in Kafka and I followed these steps

1. I did create a sample topic called my-topic with single partition

   
   spatil$ bin/kafka-topics.sh --create --zookeeper localhost:2181 --topic my-topic --replication-factor 1 --partitions 1
   Created topic "my-topic".
   

2. I used describe command to verify that my topic has actually single partition

   
   spatil$ bin/kafka-topics.sh --zookeeper localhost:2181 --describe --topic my-topic
   Topic:my-topic PartitionCount:1 ReplicationFactor:1 Configs:
    Topic: my-topic Partition: 0 Leader: 0 Replicas: 0 Isr: 0
   

3. Then I did execute alter command on my partition and changed number of partitions from 1 to 3

   
   spatil$ bin/kafka-topics.sh --zookeeper localhost:2181 --alter --topic my-topic --partitions 3
   WARNING: If partitions are increased for a topic that has a key, the partition logic or ordering of the messages will be affected
   Adding partitions succeeded!
   

4. I did execute describe command on my topic to verify that it actually has 3 topics

   
   spatil$ bin/kafka-topics.sh --zookeeper localhost:2181 --describe --topic my-topic
   Topic:my-topic PartitionCount:3 ReplicationFactor:1 Configs:
    Topic: my-topic Partition: 0 Leader: 0 Replicas: 0 Isr: 0
    Topic: my-topic Partition: 1 Leader: 0 Replicas: 0 Isr: 0
    Topic: my-topic Partition: 2 Leader: 0 Replicas: 0 Isr: 0