Cancelling appointment

I've almost completed a difficult switch from Sky that left me without broadband and phone for six days. The switch date was 16th of April but failed due to a broken external cable.  I was offered an engineer's appoitment on the 26th but asked for an earlier one. I was ccnnected  on th23rd.
 Today I've received two texts advising me of an appoitment on the 26th. I've replied "change" to both of them. Is that all Ineed to do?. It is still showing on my account.