I think what the op is trying to say is he has two basses and he wants to switch knobs from one to the other but the shaft size/style is different and will not provide the opportunity to make the change of just the knobs them selves without changing the pots as well.
He wants to know if he can change the pots to which the answer is, if you know how to solder yes, if you do not, it's probably cheaper to buy the knobs you want to fit the pots on the bass you want them on.
Again just speculation as to what I think he is trying to convey.
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