1) Go to My Account > Agents
2) Choose a specific agent, and open it up.
3) For each of your tours under the agent that you have chosen, click on "ALLOW PRICE MARK-UP & NAME CHANGE FOR THIS TOUR". See screenshot below.
4) You have now allowed that agent to sell the tour under a different name and also set it at any rate they choose as long as it is higher than the price you have entered.
5) You can also set a new deposit rate, the agent is not able to control this.
6) If at any time, you would like to return to default settings for this agent, simply disable the check-mark for "ALLOW PRICE MARK-UP & NAME CHANGE FOR THIS TOUR" and that agent will then be subject to all your default prices and deposit rates.