Linked server update connection string -SQL

Hello,I need to update connection string of a few linked server from server A to server B . What is the best way to do it ? I know we can drop and recreate however doing this also drops the logins which I do not want to do .I read in a few blogs we can use EXEC sp_setnetname I am not clear what parameter values to use if this is the right way to go.Thanks,PSB