Where an arbitrator ceases to hold office, the parties are free to agree—
If or to the extent that there is no such agreement, the following provisions apply.
The provisions of sections 16 (procedure for appointment of arbitrators) and 18 (failure of appointment procedure) apply in relation to the filling of the vacancy as in relation to an original appointment.
His ceasing to hold office does not affect any appointment by him (alone or jointly) of another arbitrator, in particular any appointment of a chairman or umpire.