Port impedance of AGILENT Network Ananalyzer

Hello Friends,

Any body know that how to change the port impedance of Agilent Network Analyzer, for example if i want to measure a matching network of 20-50 ohm measurement then how i have to change the impedance of port 2 to 20ohms in network analyzer I have done with Anritsu but i can't found any option in Agilent, can anybody help me?

you might want to post the model number of analyzer you are using. agilent makes like a hundred different models.

N5244 PNA-X 10MHz- 43.5GHz