How to set a conditional token in a Simple XML dashboard?

I have a drop-down input field that uses a token `$office_token$` to set the default value. $office_token$ is received from another dashboard when doing a drilldown as part of the http request. If the token is not received, the default is not present and the input panel stays disabled, I would like to be able to use this even if the token is not received, so I need set the token to some value if the value is not received in the request. I tried a conditional statement to check if the token is null, but it did not work. Also tried a few other things, but will try to keep the question short. Is there a way to do this in Simple SML? D_1_2_NT someValuemy querysome office fieldsome office field$office_token$ [...]