It is possible to associate a change to a ticket via API while creating a ticket. Please take a look at the Curl Command given below: 
Use this link to create a ticket and associate it with a change.
How do I link Change and Ticket using API?
How do I link Change and Ticket using API?
It is possible to associate a change to a ticket via API while creating a ticket. Please take a look at the Curl Command given below: 
Use this link to create a ticket and associate it with a change.