Well, you can change it as often as you want but unless you do the old settings stay in effect (in TacOps some get reset when they are activated). An important aspect of TacOps is multiplayer per side, and usually the commander will tell his player what SOPs to give to their units (unless some units have good reason to be different). It is pretty common to leave the "pop smoke and retreat option on for 2/3rds of the game until the moment for a decisive engagement has come.
If you look at the options you will also see "set all ground units", which is obvious and "copy". That feeds a copy'n'paste mechanism where you can paste by clicking a bunch of units or by drag-selecting them and then paste.
SOPs alone are not good enough, BTW. In addition, you need speed settings. TacOps is slightly higher level and abstracts everything into "combat speed "which only differs by terrain, but not from orders, which is a mistake IMHO. However that may be, in CM you would in any case need an additional speed setting.
But it would still greatly simplify CMBB, instead of all that hunting, move-to-contact etc. stuff you would have "slow, combat speed, fast" and in addition the SOPs. Remember that you don't need top visit the SOPs every turn, so you can happily plot away fast and slow moves all while the SOPs stay in effect. </font>