If I transferred from ATD 2020 to ATD 2021 and cannot attend the new dates, how do I change my registration? Natasha Porter Updated September 28, 2020 19:29 Follow Please contact ATD Customer Care for assistance. Email customercare@td.org or call +1 703.683.8100 or 800.628.2783. Related articles If I have to cancel my ATD 2021 conference registration after it has been transferred, what is the policy? Why is the ATD 2021 International Conference & Exposition starting in August? When can I learn more information about ATD 2021? TRAVEL AND HOUSING