Hello @Natasha-A0,
There isn't a way to edit that after having set up the payout method. The name is fixed at the time of setup.
The best option would be to contact Airbnb support and ask if they can change it.
Failing that you could:
1) temporarally set up a new payout method
2) make the new method the default one
3) delete your current method which has the incomplete name
4) re set up that method but with the complete name
5) make the corrected method the default one again
6) delete the temporarilly set up method
7) wait for your corrected method to be verified and have status "Ready"
You'd then have to hope that all that didn't confuse Airbnb's payout system 🙂
Steve.