I'm definitely inexperienced with Beyblade specifically but from what I can gather reading the rule-set for X and the match types. It appears that once the cutoff for presentation has passed, no changes can be made to the individual Bey itself.
The Judge's guide states:
Quote:After completing the inspection of the Beyblade Parts, give them back to the player, unassembled.
So once you've reassembled your Bey in secret before presenting to your opponent you would essentially make your final choice there before you get any information about the opponent's selections. And from what I can see about changes between launches that pertains to your question, I can't see anything that would present a window for you to alter the construction of the Bey after it's been presented. Hypothetically if you lost via a burst in a format where you would re-use the same Bey then I suppose you could? While not specified I imagine it's implied that the construction remains the same throughout the duration of the match. As stated in the X Format Rules guide.
Quote:Once a blader is set, they may not change their Beyblade(s) or launcher(s) for the duration of the match. Bladers must clearly announce the spin direction of their Beyblade(s) to their opponent and the judge. Beyblades must be launched in the direction that is fully compatible with the launcher being used.
While it doesn't specify, I imagine the only way you could is if it was covered under a spin direction type rule where from what I understand some Beys/Launchers are able to spin L and R depending on a setting. Again, all mostly speculation but that's my understanding from reading.
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