Instance number phase configuration

Hello All,

I´m performing a Enhancement Package upgrade in our sap system to EHP3, but I´m stuck in phase configuration (PREP_INSTALL/RUN_REDBSCPY_INIT).

This error show the following message:

ERROR: The port 3601/tcp is already occupied.

       This port is reserved for the shadow system and must be freed.

       Check the configuration in C:\Windows\system32\drivers\etc\services

       and make sure that the port is free.

Is it any way to chose another  instance number like "02"

Thanks