Originally Posted by DaveSFO

This is something you should take care of immediately. If you can't access your reservation with the eticket number then most likely OZ hasn't received it from UA. After some amount of time (don't know how long exactly) the reservation will end up getting cancelled since it has no eticket number associated with it. Calling OZ and giving them the number will take care of that and in the past I've been able to bring up the reservation with the eticket number immediately after giving it to them.