Possible Duplicate:
How do I upgrade to the development release (aka. Ubuntu+1)?
I have Ubuntu 11.10 installed in my PC. Is it possible to upgrade to 12.04 from 11.10 itself. Without uninstalling 11.10 and then installing 12.04, is it possible to upgrade directly from 11.10?
To upgrade from Ubuntu 11.10 or Ubuntu 10.04 LTS on a desktop system, press Alt+F2 and type in "update-manager -d" (without the quotes) into the command box. Update Manager should open up and tell you: New distribution release '12.04' is available. Click Upgrade and follow the on-screen instructions.
Please read https://wiki.ubuntu.com/PrecisePangolin/TechnicalOverview/Beta2 as Beta releases can have errors
A similar question was asked and answered on Ubuntu forums the other day regarding upgrading from 11.04 to 12.04 without going through 11.10 first. So, I will refer to the excellent answer provided by Kansusnoob here
Link to a previous answer on another site
Note this comment by kansusnoob:
There are now three ways to upgrade:
1: Using the update manager
2: Using the alternate CD
3: Using the live CD
Note how he proves, by providing this image, that the live CD can be used to upgrade an existing install to a distribution release and even do it with 11.04:
