I switched over to the data plan with tethering which has worked well for the past few months.
Last week while I was traveling the tethering connection stopped and now the option does not even show available on my iPhone. I double checked my rate plan and it still shows the data plus with tethering as my selected plan. Please let me know what I need to do to get tethering available once again.
I checked again and found that under general there was a setting for turning on the personal hotspot. Once I did this and turned it back off the option show up on the first Setting menu page as before. Not sure if I just did not notice this before or if the reset of the network settings did the trick. In any case thank you for your help!