If you are building or modifying reminder templates, then you will want to test them.

A convenient way to do so is as follows.

First set up the following:

1. a test practice location called say ZZ Test (this will enable you to process just reminders for customers whose practice location is set to ZZ Test)
2. a test customer say ZZ Test (whose practice location is set to ZZ Test) who has a patient say ZZ Dog. 
3. two test reminders called say ZZ Test1 and ZZ Test2 (you need 2 if you are want to test grouped reminders)

Now call up Patients|Medical Records|Reminders for ZZ Dog and use New to create two reminders, one for ZZ Test1 and the other for ZZ Test2. For each, add an item for each type of reminder (Print, Email, SMS, Export or List) that you want to test, eg:

Now go to Reporting|Reminders, set the Location to ZZ Test and you will see something like:

You can now press the Send All button and it will send these reminders.