Availing the offer

I was on the $15 subscription till a few mins back. I cancelled it as I didn’t need it for the next month. After cancelling I came across the offer of $8 per month for the same. I was to avail that offer but I want it to start after 23rd August as till then I have access to the previous subscription which I just cancelled. Can anyone help me. I want to take this offer but want it to commence after 23rd July. @Offer