Depends on who you actually have. If you have Spectrum (formerly Brighthouse) you have to wait 31 days before you can sign up again to get the promo rate (same address and same last name is no-go). Not sure about the others like Comcast but I would check to see if they have the same kind of restrictions.
Only Spectrum/Time Warner is available without a contract or dish in our area outside Austin. Numerous times we've played the cancellation game to renegotiate the fee but last spring they weren't offering a good deal AND had jacked up our internet-only fee to $125/mo. Since we were about to leave for a month, I cancelled & returned their equipment. When we returned, we decided we needed to sign up again, & we were already at the 31 days required. Brand new, free modem, & a promo rate of $45 for OK speed. I'm happy but still furious that this is necessary.
At the same time, DS moved to a downtown Austin apartment, & had his choice of Google Fiber, ATT U-verse, or Spectrum/Time Warner. He went with Google Fiber for internet-only: $50/month that is not a promotion, great speed, included equipment (wired & wifi) that was delivered & installed by a very knowledgeable & professional tech. Wish we had that kind of competition.