Be very careful what you mean by this.
Say it to a mangement type, and any surprise, no matter how trivial will introduce doubt.

It's hard, sometimes impossible (well impractical) to predict all the impacts of a change. What you should try to do is verify critical functionality.

An example might be two segments of network can still see each other, but one device which was bodged in had a weird and wonderful route which no longer works.

Be clear about what you are and have tested for.

Otherwise you'll get rolledback in an unnecessary panic and have to do it all again.