Thanks again. This is the response from the Chase rep via SM:
Thank you for contacting Chase about switching to a
United MileagePlus Explorer card.
We value your relationship with Chase and want to ensure
we address your needs as a customer. Let me inform that
the annual fee on your United MileagePlus Club card
account ending xxxx is $395.00 and this is due to be
charged on May 01, 2016. Please know that your account was
opened on April 28, 2015 and as your account is open less
than 12 months, it is not eligible to change to a
different product. Please know that the annual fee will be
automatically credited when account is closed within 90
days of billing. Please reply to this email on or after
April 28, 2016 to request to downgrade your existing card
and we will be happy to review the account further.
Thinking about some of the advice received above, if instead I were to close the account and then apply for the Explorer (or other Chase Card, like the IHG) would I be eligible for the sign-up bonuses?