Subject to restrictions being in place regarding presenters giving multiple presentations, it should be acceptable for your co-author or colleague to present your material for you. However, it is essential that you inform the Conference Content Executive of the name of the new presenting author before the author registration deadline, as your failure to register by the deadline will mean that your material is removed from the program. The Conference Content Executive email address will be available on the abstract submission section of the conference website, which you can find here.