I have not read through 10 pages so maybe somebody else answered this, but why would Dak agree to this?
Dak has a contract in hand signed by the team. If the team wants to alter that contract in any way, shape, or form, they have to go to Dak and his agent and they have to agree to change the contract. Dak is good as is, the Cowboys are the ones that are going to Dak, not the other way around.
So why would Dak agree to remove the no trade clause? You think he wants to wake up one morning and find out he just got traded to the Texans? A no trade clause is valuable to a player, so you are going to have to offer something of value in exchange to get the player to agree to remove it.
So, what are you offering Dak that he does not have in his current contract that is valuable enough for him to agree to remove the no trade clause? How many more millions per year are you offering over what his current contract calls for? Remember, Dak is good as is with his contract, its the team that is wanting to make changes and that dont happen unless the team offers up something of value to make it worth it to the player to change an existing contract.