It is a pledge and was contained in the 100 day programme. This is what he promised to do. If Ranil is not suitable there can be a no confidence vote and can be removed. The plan B would be to dissolve the parliament and go for early general election . I cant see any illegality here as this was in his 100 pint plan and people had voted for that. MR violated constitution like no other president. He even interfered with the Judicial Service Commission which is an offence under the constitution. When this was revealed he removed the CJ and the secretary to the JSC. This is clearly abuse of power and violation of constitution.