Switching program post application

I currently have applied to my local union for telecom as one of my parent’s friends recommended it after college didn’t work out. I’ve finished the application process and have a date set to take my test, but after looking through it more I think inside wireman fits me better. Would it be possible for me to switch which program I applied for at this stage, or would I probably have to open a new application? I also don’t want it to look bad on me and seem careless on my application if I do switch, but I don’t know if I can avoid that.