Yoroi Testnet delegation change

I faced issue on Daedalus test net wallet sync. Then I recover my wallet on yoroi test net wallet. any one have idea how we can change delegation on yoroi wallet, I tried directly to change delegation with out UN delegate wallet, it is showing the transaction pending, then fail. Shall I delegate current pool, then delegate new pool, or there are some other process?

You don’t have to undelegate before switching pools. You can just switch pools directly.

Sometimes transactions fail temporarily and then end up succeeding. This is due to network conditions of the testnet so I suggest usually waiting a few minutes for the transaction status to be accurate.