Removing or adding a race

I have questions on adding and removing races.

I’m on the high volume MTB plan. My emphasis this year will be on XC and marathon MTB.

I’ve added races twice now. Each time it has totally reset my training plan.

I need to delete one of my B races because I am not able to attend.

I’m a little worried after last time with my whole plan changing about it going backwards in my buildup. Last time it reduced my training volume by quite a bit.

So going forward if I want to add a C race (one by definition that is a race that you train through) should I actually do that or just swap in a similar workout for the race? Don’t really need any taper on these or to stop lifting just might like to rearrange the workouts for the week.

Second, what should I expect if I remove a B race? Is there a better time than another to do it? Earlier or later for instance? Beginning of a week or end? Will it always drop down the volume of the following weeks?

As described @Velorick, I would just swap in a similar workout for the race (i.e., hot laps workout).

It really depends. If you remove the race then the taper will be removed and the logic resets (number of base, build and taper weeks leading into B and A races). The typical weekly volume should be guided mostly by your fitness numbers (i.e., not too affected).