Change to Innodb to File per table

[IATechsupport]

I have just been bitten with the default innodb setup on plesk storing all table information in the shared file.

I want to move to innodb file per table.

I have found that i need to add the following to my.cnf to enable it.

innodb_file_per_table=1

What i dont know is if i do make that change what happens to databases already setup on the server?

thanks