They could also do what they have done in the past. When they longer wanted to support 1874, they just moved everything up to 1914. Then they found or created events within the history of the Society to prove the fulfillment of bible prophecy.
Now, they could eventually abandon 1914 and move everything up 20 years to 1934 to support the destruction of Jerusalem in 587 BCE.
After listening to the comments of the loyal Witnesses today at the meeting, proclaiming their undying, unconditional support for the "Slave" and its Governing Body, I am sure they can get away with this.
New light can accomplish anything!