Thanks, I backed up my phone and deleted texts messages from that family member. Toggled off imessage and powered down phone. After 10 minutes powered back phone. Toggled imessage on. Got message 'waiting for activation'. Powered phone down again for few minutes and turned it back on. imessage was back on. Texts now go to right person.
All this started with my wife and I plus kids sharing the same appleid and switching over to family sharing with each person have our individual accounts. I had to deregister one of the phone numbers linked to a family member as it was attached to my imessage without any ability to edit and remove that phone.
I am planning to restore phone and see if the text messages continue to behave! Thanks Again.