On Fri, 1 Mar 2019 10:42:22 -0800 (PST), wrote:

I have an overhead light fixture with 3 40 watt bulbs. one of them burnt out. can I replace only the burnt out bulb with an LED bulb? What if any would be the consequinces? Thanks for a reply

Actually mixing them is a way to get around those devices that do not
like CFLs and LEDs. As long as you still have at least one
incandescent in that down stream circuit the dimmer, occupancy/motion
sensor or smart switch will usually still work fine.