Hello Naresh,
SAP does not provide a direct option to change the Payload name in Moni. For this you need to develop a Custom Adapter Module and use it in your File sender channel.
You can see the reply from Shabarish in the below link for the code to be written in the Custom Adapter Module
Controlling filenames using PayloadZipBean
Please let me know if you need more information on this.
Regards,
Nitin Deshpande