@RyRy11 I think the PL rulebook bans shirt clashes and sock clashes, but it doesn't ban shorts clashes. Therefore, City have the option to not wear change shorts when they come to OT. I also think that the CL doesn't allow shorts clashes although I do know for definite that the EFL doesn't tolerate shorts clashes so I think City would have to wear either sky blue/ navy shorts if they had to play a tie in the Carabao Cup at OT. Just to make another point, but some teams don't like wearing alternate shorts so they tend to use their away kits instead (Real Madrid tend to do this). Others like Arsenal have also done this for a long time, although Arsenal have worn red shorts with their home shirts a few times in the last few years. For what it's worth, City have changed shorts at OT before, as the link below shows. There's also an account on Twitter by the name of Museum of Jerseys who writes articles about kit info such as this.
http://news.bbc.co.uk/sport2/hi/football/eng_prem/2715989.stm