Nín xiān qǐnɡ.

您先请。

After you.

Notes:

您(nín): you(repectful form)

先(xiān): first

请(qǐnɡ): please

Example:

A：您先请。

     Nín xiān qǐnɡ.

     After you.

B：谢谢。

     Xièxie.

     Thank you.