How can I change the fps of video without restarting the video stream, which is being played by ffmpeg command?

Question

I am playing the video (.mp4) in VLC by this below command in terminal:

ffmpeg -i input_file.mp4 -crf 18 -c:a copy -r 60 http://localhost:1234/feed1.ffm

Currently it is 60 fps.

Now I want to change the fps during the playback of video file, so is it possible to change the fps during runtime without restarting/breaking the video using FFmpeg? And if it is possible then please guide me.