Conditional content in Mandrill template

I am handing over dictionary keys (key value pair) to a service which in turn utilizes the api to send the email via Mandrill.

Now, if my key is blank then i dont want it to be included in the email. Like in the following scenario, i only want the link text to display if my key has some value.

<a href="|UPDATE_PROFILE|" target="_blank">change subscription preferences</a>

How can i write it some thing like or even is this possible?

if *|UPDATE_PROFILE|* IS NOT EMPTYBEGIN<a href="*|UPDATE_PROFILE|*" target="_blank">change subscription preferences</a> END