How do Request Tickets and Calling Cards work?

I know I have these two items (I've seen prompts about their existence) but I don't know how to access or use them. I've exhausted all available requests and don't see an option to use one of these features to make more requests available. The Beginner's Guide explanation for Request Tickets isn't helpful either:

What do Request Tickets and Calling Cards do and how do I activate them?

I just worked out that you can use a calling card to 'call' one of the animals on your 'Contacts' list. You can call the ones that aren't visiting at your site.

I got a prompt to use a request ticket when I asked an animal "Need anything?" after I had fulfilled a few of their requests.

Request Tickets are used to have the camping animals (not in your campsite) request more items. Useful for leveling up the friendship levels faster.

This can be used by: going over to the camping animal, and asking "What do you want?".

Calling Cards are used to call over an animal in your contact list that's not in your campsite, and is not camping right now.

They can be used by: selecting the animal on the contact list, and pressing "Call".

Request Tickets

Neighbors rotate on the map every few hours. Each rotating neighbor has three requests to fulfill, but that isn't enough to bring them to higher friendship levels (early animals require level three relationships to invite, but that later increases to five, seven, etc.) so you can add another round of requests (three) with a Request Ticket. This only works on the rotating neighbors, not neighbors visiting your campsite.

Ask one more time whether a rotating neighbor needs help, and you'll receive a prompt:

This also adds +3 relationship points, regardless of whether you finish the added requests.

Calling Cards

If you'd like to do a round of requests for a neighbor who is not in the current rotation or visiting your campsite, a Calling Card will bring the character to a specific camping location. First, visit a location that has one or no animal campers. Then "Call" the character from the Contacts tab for the following prompt:

Only two animals can camp in a single location: