You can signal interest and maybe draw someone else in now.
http://www.nintendoworldreport.com/news/71051/pokemon-go-adds-new-feature-for-raid-battles
Pokemon Go has rolled out more changes to the raiding system.
An update today has added the ability to "RSVP" or schedule a time for participating in a raid battle. The signal includes an option to invite friends to participate.
This differs from a previous system of "EX Raids" in which a player would be invited at random to play a particularly challenging raid: this feature was depricated in 2020 as part of the game's pandemic adaptations.
