How to pause the subscriber end of transactional replication
Replication runs using "Agents"--essentially external executables that do the work. For transactional Replication, you have three agents:


Snapshot Agent - this is the process who does the snapshot to initialize Replication (assuming you aren't initializing via another method. Most people use snapshots). There is one per publication. It lives on either the Publisher or the Distributor.
Log Reader Agent - this is the process that reads the transaction log on the publisher, identifies changes, and writes those changes to the distribution database on your distributor. There is one per publication. It lives on either the Publisher or the Distributor.
Distribution Agent - this is the process that takes changes from your distribution database and pushes it to the subscriber. There is one per subscriber. It lives on either the Subscriber or the Distributor.


The standard setup is that the agents run as SQL Agent jobs. If you want to stop distributing commands to a subscriber, simply stop the jobs. You can find distribution agents based on the job category of REPL-Distribution. The job name will be composed to include publisher/subscriber info to help you identify the correct job to disable. Those values may be truncated when making the job name, so if you have multiple distributors, you may need to look at the distribution job step itself to be 100% sure you have identified the correct job. 

Note you can also confirm the correct job by querying the distribution database--but I generally find it quicker and easier to look at the job itself.