I have a new working implementation of Ex13 (w/Outlook 10,13) and along the way I purchased and installed a single-host certificate instead of a SAN certificate, not realizing there was a difference. Obviously to get it to work I have both internal and external URLs set to the same name. I need to change this, so I purchased a new SAN certificate with the correct names. I have gone as far as installing it in Exchange but have not assigned any services. This morning I got a complaint that a meeting invite failed and I wonder if it is related. Is there anything I need to take into consideration doing this? Can I just assign it to the services and de-assign the old one? How will Outlook get updated? Somewhat time-critical. Thanks.