This tutorial should help you merge Accounts or Contact. Before moving forward, make sure your Authentication works and you understand the Key Concepts of the Pipeliner API, and make sure you know how to use API parameters
When you have two similar Accounts or Contacts you can use merge functionality to move all data from a duplicate to the master record. The Duplicate will be deleted at the same time
Merging Accounts
Merging Contacts
Example of Account Merging
The merging functionality through API works in the same way asin the Application.