Mutations in a docked pose

Hello.....I have the following query

I have docked 2 proteins and found an interesting pose.

Now I wish to mutate one particular residue from each of the two docked proteins and analyze the results in the same pose which I got earlier.

Is this an effective way to analyze the effects caused by the mutations ?

Or should I mutate the residue from the 2 proteins separately, load those 2 proteins again and dock them again ?

In short, can I mutate residues in a particular docked pose using the Build and Edit Proteins feature? or should I dock the proteins again everytime I mutate ?

If I dock the proteins again, I would not get the same pose which I got earlier. And so I won't be able to compare the differences between the non-mutated and mutated poses.

Does it make a major difference to the ZDOCK score and ZRANK if I mutate residues in an already docked pose ?