After the change in the closing states of service now, i am now able to resolve the issue of reopening incidents.
I am now using 6,7,8 as closing states in service now. Before the change, it was 7,8 in closing states which was not allowing me to create different incident for each alert.
But I came across one more issue after the change in states field which is that if anybody resolves the incident accidentally or purposely even when the alert is active on solarwinds, it resolves the incident and does not reopen
