@Cassandra22 If you're using Chrome, just open Airbnb in Incognito mode. Then, you'll be automatically prompted to create a new account.
As it's against Airbnb policy for one person to have multiple user accounts, the new account will have to be under the ownership of your client. You can send a referral link to their email (I think co-hosts are still eligible for the referral bonus), prompt them to submit photo and ID for verification and payout/tax data, and assign you as the co-host. Of course you can assist them through all of this process if they don't have time or access to a computer, but they should have a private password and exclusive access to their account.
As the co-host, you'll be able to set up the listing, manage the calendar, and correspond with the guests - all from your own user account. So all the work of hosting can be delegated to you, but the burden of liability falls on the owner, and their listing won't be mixed in with yours; if your business relationship doesn't work out, the owner can still transfer co-hosting duties to someone else. You'll need to arrange your compensation payments outside of Airbnb..
Info: https://www.airbnb.com/help/article/1534/
