If you need to move a staked EOS from um account to another, you would need to unstake it, wait 72 hours and then stake it to the new account. Is there any way to do it quickly by just changing the account that receives the stake?
You cannot get around the unstaking process if all of your EOS is staked on both accounts.
With that being said, if you have liquid EOS on another account, you can stake that EOS to another account:
cleos system delegatebw from_this_account to_this_account "1 EOS" "1 EOS"
from TEXT - The account delegating bandwidth receiver TEXT - The account to delegate bandwidth from stake_net_quantity TEXT - The amount of EOS to delegate for network bandwidth stake_cpu_quantity TEXT - The amount of EOS to delegate for CPU bandwidth