nonelite vs elite vs upgrade using points
 

If a ticket was purchased on line from ewr to mco round trip is the ticket upgrade able

This is all on continental.com.

1) If you're elite, then yes - if there are seats available for upgrade.
2) If you're not elite, then it depends on the fare class.

I assume you mean using miles - if you're talking about using $$, then you need to pay the fare difference - probably plus the $100 change fee.