The UpdateExpirationForHIT operation allows you update the expiration
time of a HIT. If you update it to a time in the past, the HIT will be
immediately expired.
mturk_update_expiration_for_hit(HITId, ExpireAt)[required] The HIT to update.
[required] The date and time at which you want the HIT to expire
svc$update_expiration_for_hit(
HITId = "string",
ExpireAt = as.POSIXct(
"2015-01-01"
)
)