instead of surrendering, how can you give over control to a teammate?

you cant

Edited 7/30/2017 15:14:01

By giving your account login details to your teammate for the whole game.
By gifting a territory to you teammate for individual territories.
By airlifting armies from your own territories to your teammate if you want your teammate to have your armies.
By transferring your armies from one of your own territories to one of your teammate's territories.

No other ways exist unless you put this idea on Uservoice or search for a similar idea like this on Uservoice and up vote it. Link to Uservoice: http://warlight.uservoice.com/.

https://warlight.uservoice.com/forums/77051-warlight-features/suggestions/1240763-teammate-takes-over-for-booted-surrendered-player

Fourth most upvoted suggestion.

Give him your accounts details if you trust him enough. But make sure it is not for coins, otherwise you could be suspended.