Crystallisation of foreign exchange liability allows banks to convert ECB guarantee obligations into rupees after application. Authorised dealers may convert foreign exchange liabilities arising from guarantees or letters of comfort for External Commercial Borrowings into Rupees in select cases where circumstances warrant; they must apply to the Chief General Manager, Exchange Control Department, External Commercial Borrowings Division, Reserve Bank of India, providing full particulars including borrower name, amount, maturity, circumstances of invocation, date of default, impact on overseas branch liabilities and other relevant factors.