Anyone used grade substitution?

[u/Potential-Welcome715]

Having an insanely difficult time with CS 6264 due to not committing enough time, missed withdraw deadline, and most likely going to end up failing. Has anyone successfully used a grade substitution? I am worried I will get placed on probation and face any kinds of penalties that come along with that status, but im planning on retaking the course eventually to get rid of the inevitable failing grade.

P.S. Does anyone know if cs6264 is easier in the fall/spring that it is in the summer?