Yes and no. If your G-code is absolute then that would be easily possible because each statement would stand on its own. "Go here" "Do this". However 99% of code generated by other programs use relative moves that use the prior position as a reference. So instead of "Go here" it becomes "Move a little more".
You should be able to see that if you stop G-Code execution, back up a bit and Go the next instruction will likely be "move a little more" from wherever the tool is at right now instead of where it would've been just before reaching that same instruction in normal execution.
What this means is normally, no, you can not just back up and redo.
If you want to do that you need to learn enough about G-Code that you can recognize the absolute moves that are lightly sprinkled about in most G-Code and back up specifically to that point in the code before, "continuing from here".
If there are no absolute moves (rare) then it's easiest to just re-run the entire job.