sp_cycle_errorlog
Every time SQL Server is started, the current error log is renamed to errorlog.1; errorlog.1 becomes errorlog.2, errorlog.2 becomes errorlog.3, and so on. sp_cycle_errorlog enables you to cycle the error log files without stopping and starting the server. Return Code Values 0 (success) or 1 (failure) Source: https://docs.microsoft.com/en-us/sql/relational-databases/system-stored-procedures/sp-cycle-errorlog-transact-sql?view=sql-server-2017