How can I return uncaptured funds via REST API?

[SherryLLL]

I have a transaction that has been authorized and captured multiple times.

There are still uncapped funds in this transaction. I want to return this part of uncaught funds to the user. How to handle it through rest api ?

choose  munual capture ;

example : 

total authorization funds :  4.96 dollar
first capture : 2 dollar

second capture : 2 dollar
remain authorized but not captured funds: 0.96  dollar
i want to return 0.96 to user through rest api.   help me. thanks