There is. That little pop up where you acknowledge or decline the order when they send it to you. Has only been there a few months. Just decline if you have to.
When I started I was told the assignment was yours and set in stone no matter what. If you lacked competency for it than you better find someone to team up with to get you competence in it..Pretty hard line. I was told if you turn down more than an assignment or two just because it was "hard" you would probably be off the panel as they explained they didn't have time to baby people and put it back through the assigning system.
I just have been away for vacation, and a long overdue VA vacation (2 weeks away for real, 6 weeks as far as the VA goes. With the current market the VA fees are jamming me up and costing me money, so they can hold off a bit). The day I was going to call in my vacay dates they sent three over. I called the next day and said I COULD stay active a few more days and knock these out and will gladly do so if turning them down will hurt my VA status. The VA rep said it was fine. I double checked and reiterated I was told turning down assignments or kicking them back was a big no no and didn't want to jeopardize my status. He said they did chart everything and keep track of who does what and why but unless its a consistent pattern, its not a big deal. I hit the decline button and away the three went..