As miners reduce production and there are fewer Bitcoins circulating in the market, the price will rise as expected.
It's worth noting that the upcoming reduction in block reward doesn't equate to having fewer Bitcoins in circulation and considering that Bitcoin is still inflationary, I don't think we'll see a significant positive impact on its value
[I hope I'm wrong for the latter part and hodlers would benefit from this event].
Perhaps Op is referring to the reduction in the supply of new mined Bitcoins. The reduction in the block actually doesn't reduce the bitcoin in circulation directly but it minimize the rate of new mined Bitcoins coming into the circulation which I think is what Op is talking about. If so, it would have impact on the market even if not immediately but definitely. Although, it can create high volatility which I believe we already experienced and will continue to experience more in the coming days for short time. I see nothing to be panic here, hodlers who exercise patience will definitely benefit from it.