Changing EIGRP delay doesn't change routing zero's route

I have two ASR 1002X's that connect to a Cisco catalyst C3850-12XS. Each ASR is connected to a different ISP. All 3 devices use EIGRP for routing. ISP1 ASR has delay of 1000, ISP2 ASR delay 1500.

Needed to manually failover from ISP1 to ISP2, so I changed the EIGRP delay to be 2000 across the ISP1 connected devices. EIGRP did not failover to ISP2? What can I do that is non-evasive to force EIGRP routing change? Would clearing routes or resetting EIGRP drop current connected outbound users?

We have similar setup across several sites, but we are using Cisco 2900 routers and Cat 3750E connecting to two different ISP's on those sites. all running 15.x IOS code. When we change the delay on ISP1, it always forces traffic out ISP2 on those sites.

Thanks