FRLG (Switch 2 Version) - Reset giving Celio the sapphire

Hello,

I already caught the roamer. Now I would like to obtain it again, but this time I want one that I can RNG manipulate. Is there any way to reset Celio or retrigger the event where I give him the Sapphire so that a new roamer is generated which can be rng manipulated ?

Is there a ACE code for that ?