German phrase
Können Sie mir helfen, ~ umzubuchen?
Meaning
Could you help me rebook ___?
When to use it
A polite request to rebook. Used at a counter or by phone to change travel plans.
Example dialogue
Können Sie mir helfen, meinen Zug umzubuchen?
Could you help me rebook my train?
Ja, gern. An welchem Tag möchten Sie umbuchen?
Yes, of course. Which day would you like to rebook for?