mostly online donations. he s also creating some major drama ahead of the next gop debate. nbc s kristen welker reports. reporter: teaming with fellow candidate ben carson, donald trump is threatening to boycott the october 28th republican presidential debate on cnbc if it lasts longer than two hours and doesn t include opening and closing remarks. in a letter to cnbc, trump and carson describe their demands as very reasonable format changes. cnbc, a sister channel to nbc, says it is still in the process of discussing its debate format but notes it has not done opening and closing remarks in past debates. and in a statement, cnbc added it would take the views on the format into consideration as we finalize the debate structure. meanwhile vice president biden remains undecided. while waiting to greet the south korean president, he played coy. are you running for president? i ll answer in korean. i m here to greet president park. reporter: sources close to the vice president say