Nirupama Raos appointment as the next Foreign Secretary has set off hectic lobbying in South Block as a clutch of ambassadorial assignments will now be up for grabs. Indian ambassador to Malaysia Ashok Kath is the frontrunner for replacing Rao in Beijing,while Secretary West Nalin Surie,who lost out in the FS race,may go to London. Meanwhile,Alok Prasad,the Indian High Commissioner in Colombo,is also set to complete his term. The top post in Dhaka may also fall vacant slightly earlier than expected.