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