How do I change this frequency?

Currently, we do not have the option to modify the frequency for uptime monitoring. The default settings for monitoring frequency will apply as per the subscription plan selected. 

Please note that the monitoring frequency for each subscription plan is different. 

For instance, for the free subscription plan, the monitoring will be carried out every hour. For the Plus plan, the frequency is every 15 minutes, and for the Pro and Max plans, it is every 5 minutes.

 I hope this information helps. In case you have a Pro plan, here is an example that will help you understand the monitoring frequency.