What helps
'Enjoy it', 'you'll see', 'what freedom' close a tone they did not choose. If they are glad, you can be interested. If they are lost, you do not force the enthusiasm.
They do not have to tell you what they will do with this life. In the days after, 'so, this new life?' is a review in disguise. A simple moment, which they can refuse, is enough.
Time passes: it is no longer 'the transition', it is their life. The date is not declared a good chapter. You follow what it is for them.
Concrete example
"Thinking of you in this change. No need to tell me what comes next."
Key takeaway
- No slogan about the next chapter.
- The tone is theirs, not a greeting card's.
Try next time
A present-tense sentence, with no plan for their new setup.