If a person mistakenly adds a floor drawing to an incorrect floor, there is no method using IBM TRIRIGA tools (TRIRIGA itself or CAD Integrator) to actually remove the graphic from the floor record. An RFE (http://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=109781) has been created to address this issue. I respectfully request that you vote for this RFE if you would like to see the CAD Integrator product have the ability to remove the graphic from the floor record. If you do not currently have an IBM ID, you can sign up for one at no cost.
Note: There is a similar forum thread at the following: https://www.ibm.com/developerworks/community/forums/html/topic?id=addfdf16-e010-4c3b-bc51-007924a6d409&ps=25 that provided a work around for this issue.