LEGALLY yes. BUT anyone that's paying attention to the process knows its not being done legally or even morally. Cruz assholes stole delegates in Ga where that POS didn't even win a county!
The negotiation is on for a Kasich and Rubio third party ticket to (1) derail and punish Trump and (2) spotlight the GOP insurgents and drive them from the Party. That will open up 2020 for TC, JK, and MR.