How to stop payment for vendor after executing APP

Hi experts,

1. I run my app and completed all the steps other than print out medium. Later I noticed that I made a mistake of wrong payment to related vendor.     How to stop the payment and re-execute the program.

2. If it in case of automatic payment like EBS and how to stop the payment for the vendor.

Please clarify the above two questions.

Thanks in advance,

Anu.