colour changing

We need some more information...

Are you asking how to make a fixture alternate between blue and red?
What fixtures are these?
Does this really need to happen in 1 cue?

yes, I wanna make a fixture alternate between blue and red. the fixtures are the martin 550. And I really need to do it in 1 cue.

If you're going to be alternating between red and blue, then your best bet is to create a different cue list containing only the color information.

That way in the "primary" cue list, you can use a comment macro to trigger and release it and it only takes 1 cue on the "primary" list.

Any particular reason it needs to be 1 cue?

yes it should be in 1 cue because I don't want to do 1cue blue and another red with a duration less than 1 second. I can do it only with static projector with cmy or rgb intagrated but the martin isn't equip with cmy or rgb

you could do it with the effect generator. Set the base color value on the blue filter of your color wheel, then use a mark on effect and change the size to find the red color.
The only problem with this trick is the rainbow effect you get during the transitions. You can try and add a effect on the dimmer to shut down the spot while the color changes.

I will try it