Asked by Juan Carlos to be chief witness at the ceremony declaring him successor and "Prince of Spain", Alfonso immediately agreed to do so and sent some of his supporters to visit his father in Paris to persuade him to express no opposition publicly. In return for his full support, Franco later appointed Alfonso Spain's ambassador to Sweden. But in June 1972, after he had taken up that post, Alfonso advised Franco's foreign minister Laureano López Rodó that he deemed his support conditional upon his cousin's continued loyalty to Francoist Spain. He further hinted that Spain's law of succession should be amended to facilitate Alfonso's replacing or succeeding Juan Carlos as Franco's heir or on the throne, if circumstances called for such a change.