To create a Master Schedule, you need to go to the Master Schedule tab in the client profile.  
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If your agency user can't see that tab, it's because you need to activate access for your agency users.  To do this, navigate to the Admin Settings>Role Management:
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For each role that needs to see the Master Schedule tab, you will need to allow that access:

Scroll down to the client section and then allow full access (or read only) for the Visit Plan
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