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## Exercise
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In this exercise you will continue with the Patient profile you created in earlier modules. In the first 3 steps we will use Forge to edit the profile. [Download Forge](https://simplifier.net/forge/download) if you have not done this earlier. Start by reading the case description.

<ul class="roundbox">
<b>Case description</b><br>
Hospital X has some additional requirements to the Patient profile. 
<li>The use of the social security number (BNS) should be fixed to official</li>
<li>The use of the hospital information system number (HIS) should be set to secondary</li>
<li>The contact details can be either: email address, phone and fax, which should all be captured in different slices</li>
<li>A work phone number is mandatory and an additional personal number is optional</li>
<li>Besides work and personal numbers no additional phone numbers are allowed</li>
</ul>

### Steps to follow

#### 1. Create Patient profile
Skip this step if you have your Patient profile (including slices) already in place. You will if you have completed the exercises of the [Slicing](Slicing) module.
1. Open Forge and create a new profile on Patient (or use your Patient profile from other exercises).
2. Slice the `Identifier` element and add slices for national security number (BSN) and hospital information system number (HIS).
3. Slice the `telecom` element and add slices for phone and email. 

#### 2. Extend discriminator
1. Create a new derived profile in Forge on you Patient profile.
2. Extend the discriminator for the `Identifier` slice. 
3. Note that you cannot change the discriminator path, but you can add one.
4. In the social security number (BSN) slice set the `use` to official.
5. In the hospital information system number (HIS) slice set the `use` to secondary.

#### 3. Add additional slice
1. In the `telecom` element add a new slice for fax.
2. Change the slice name to Fax.
3. Set the (fixed) value of the `system` element to fax.

#### 4. Re-slicing
1. Re-slice the Phone slice. Note that you will have to directly edit the XML (or JSON) to do so as re-slicing is not (yet) supported in Forge.
2. Add a discriminator on use.
3. Add a slice for work phone number.
4. Add a slice for personal phone number.
5. Change the minimum cardinality of the work phone number to 1 to make it mandatory.

#### 5. Changing the slicing rules
1. Besides personal and work no additional phone numbers are allowed. Set the slicing rules to closed. 
2. At which level can you change the slicing rules?
3. Would you also be allowed to set the slicing rules at the parent level (that is in the `telecom` element) to closed?

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