Have to Miss a Workout - What to Do?

I am doing a preseason, 12 week workout. There are 2 a week and the first is available Monday morning and the second Thursday morning. I have to travel for work and cannot do the 1st workout of the week. Is there a way to pull the early week workout back into my schedule and do it? This is probably a noob question but I can’t find anything in the search area that addresses this. Any help is appreciated.