Modify an instruction?

[joannahuadu]

How to modify an instruction? Can the modification be achieved in the instrumentation function? Is "instruction emulation" needed?
For instance, what should I do if I just want to apply one-bit flip in a specifc instruction (maybe the modified instruction is illegal, never mind).

Now, only inserting API(i.e., nvbit_insert_call) and removing API (i.e., nvbit_remove_orig) are found. Thus, I only found the modification in register value or memory data at memory reference address (by memory instructions).