DUBAI, June 21 (Reuters) - Saudi Arabia's King Salman has called for a public pledging of allegiance in Mecca on Wednesday to Prince Mohammed bin Salman who has been promoted to crown prince, Saudi-owned channel al-Arabiya said on Wednesday.

A royal decree published on state news agency SPA earlier said Prince Mohammed bin Salman was replacing Prince Mohammed bin Nayef in the role. Saudi Arabia's Allegiance Council had voted 31 to 34 in favour of the changes, al Arabiya said.

(Reporting by Stephen Kalin and Mohamed el Sherif, Editing by Sylvia Westall) ((sylvia.westall@thomsonreuters.com; Dubai Newsroom +971 56 216 6204; Reuters Messaging: sylvia.westall.thomsonreuters.com@reuters.net))