SET ISOLATION LEVEL allows you to specify the isolation level.
If the assigned workload server is Secondary, it can be changed programmatically to the Primary. At the session level, the following statements change the workload connection server to the Primary:
SET WRITE (nonstandard)
SET ISOLATION LEVEL REPEATABLE READ
SET ISOLATION LEVEL SERIALIZABLE
The statement takes effect immediately, if it is a first statement of a transaction, or from the next transaction otherwise.
If the above statement is not applicable, it returns SQL_SUCCESS, with no action performed. For example, such is a the case when SET WRITE is applied to a standalone server. In that case the semantics of SET WRITE is equal to that of SET READ WRITE.
The effect of the SET WRITE statement may be reverted with the statement SET READ WRITE or ... READ ONLY (SQL:1999). Also, the isolation level statement has the same effect: SET ISOLATION LEVEL READ COMMITTED