You can use Sybase Central, or if you're like me, you prefer a command line approach using a script file for various reasons (like the ability to run it repeatedly without having to click-and-clack-and-make-mistakes).

This topic in the Help describes both techniques.

The following example uses the one-step dbunload -an utility on the Version 9 demo database. Just save it as a *.bat file, edit it for your database filespec, and run it...

REM If you're a command-line kinda guy, here is my template Windows 
REM batch file run_dbunload_upgrade_v9_to_v11.bat. It does the 
REM unload-reload-all-in-one-dbunload-step, then starts dbeng11 
REM and dbisql so you can make sure the new database is up and running.

REM Be sure to stop *all* database engines on the computer you're using, 
REM before starting the upgrade.

REM dbunload...
REM -an ...  where to put new database
REM -ap ...  new database page size
REM -c ...   old database startup connection string
REM -o ...   where to put unload console display text file
REM -v       verbose mode for console display

PAUSE MAKE SURE YOU DO NOT HAVE ANY ENGINES RUNNING.

"%SQLANY11%\bin32\dbunload.exe"^
  -an "C:\temp\demo11.db"^
  -ap 4096^
  -c "DBF=C:\Program Files\Sybase\SQL Anywhere 9\asademo.db;UID=dba;PWD=sql"^
  -o "C:\temp\dbunload_log_demo.txt"^
  -v

PAUSE dbunload/reload done...

REM dbeng11...
REM -c ...     initial RAM cache size
REM -o ...     where to put server console display text file
REM -os ...    when to rename and restart server console display text file
REM demo11.db  new database to start

"%SQLANY11%\bin32\dbspawn.exe"^
  -f "%SQLANY11%\bin32\dbeng11.exe"^
  -o "C:\temp\dbeng11_log_demo11.txt"^
  "C:\temp\demo11.db"

PAUSE dbeng11 started...

REM dbisql...
REM -c ...  new database connection string

"%SQLANY11%\bin32\dbisql.com"^
  -c "ENG=demo11;DBN=demo11;UID=dba;PWD=sql"

PAUSE All done...

Olan, further tips can be found on this question.