If you're trying to manage a brand or project account.

1. Log out on Warpcast mobile
2. Create a 2nd account
3. Connect with either @supercast or @crew 
4. Log back in on Warpcast for your normal account

Now you have 2 accounts online.

If you‘re into open-source: try @herocast and contribute at

If you‘re into open-source: try @herocast and contribute at https://github.com/hellno/herocast

That's a good easy way to manage two accounts

so using one account on a browser and the other in the mobile app?

Searchcaster