The 911 calls are routed through pool 70, and cannot be changed to any other pool. Typically, pool 70 contains loop start lines, and T1's are set up in pool 890 or 891. You may need to reassign your T1 channels to pool 70, but be sure to print out your ARS tables, so you can also change them to use pool 70 again, instead of whatever they are using now.