Hi Muralikrishna,
First of all, sorry for delayed reply, was quite busy this afternoon 
But, let's see, only side you'll need to create RFC function module is target system (RFC) and at source system (ECC) you'll only need to call this function module defining your target system (see DESTINATION option for function module calls).
In this way you'd have following:
1 - program at ECC side that will call RFC function module (at 4.7 side)
2 - RFC function module at 4.7 side that will trigger (SUBMIT) target report, also in 4.7
3 - for last, your target report in 4.7
So, answering your question, it is possible to make your target report (3) to generate a file and download it at 4.7 side (application server or, locally, presentation server, whatever you pass as file path to RFC function module, and then and therefore to target program, as long as you have authorization to). In a simpler approach you'll call a program in a remote system (in your scenario that 4.7) making use of a RFC function module (also in 4.7) to allow you to. All started through a RFC call from a program in your source system (ECC).
Not sure my explanation was good enough, please let me know.
Regards,
Edgar