EC&O's initial application, made in 2005, was rejected by the planning committee last year when several local residents voiced their concerns.
The venue is currently awaiting the result of an appeal.
The second proposal, which will be considered in isolation, features a casino at the West Brompton entrance to the building and will not alter the facade of the building. A spokesman for EC&O Venues said: "Plan B addresses all the concerns of local residents. We've done our best to accommodate their needs and wishes."
If one of the applications proves successful, EC&O insists a casino would not impact its core business but instead facilitate up to £20m of inward investment in the exhibition venue.
At the moment the venue generates more than £300m of expenditure annually and supports more than 4,000 jobs across its 180 events.
However, it suggests that in order to compete within an events market in which small and medium-sized shows are the drivers of growth, the venue must invest in change.
Anthony Lyons, EC&O chief executive, said: "What this proposal will do is provide some 300 new job opportunities and facilitate the investment in infrastructure and services that will enable us to widen and increase the type and number of events that we host each year.
"For local residents it provides a level of assurance that Earls Court remains an exhibition centre. The plan has sparked off debate among a few very vocal concerned parties who have painted a totally unjustified and unrealistic picture of the consequences of having a casino in Earls Court."
A decision on both applications is expected in the next six months.