Worry Free Registration Options:

To transfer your registration to another runner (up to 2 weeks out): https://runsignup.com/How-To/Transfer-To-Another-Runner

To defer your entry to the following year (up to 1 week out): https://help.runsignup.com/support/solutions/articles/17000062915-defer-registration-claim-deferral
Entry fees are non-refundable.