Best thing you can do is stick with whatever oil the engine has been running. Switching oil isn't all that great of an idea. Also, if you do switch, stick to what ever you switch to.

This is a good listen for people wanting to learn a little about oils. Hit the little play button under the first picture. This is seriously worth your time to listen.

Synthetic Oil with Lake Speed, Jr. & Audi R8 | Adam Carolla's CarCast