Data appending to file and data deletion from file

Hi All,

I am doing a FTP to FTP scenario in which my requirement is as follows:

1. PI picks up file from FTP n clears the content of file. (Here file is not deleted only the file content are deleted)

2. When PI puts data to destination it appends the data to existing file.

Can anybody plz suggest how to handle this data clearing part of file and appending of data to file?

Thanks in advance.

Regards,

Rohan