Delete chat on grindr

Hey I hope you guys can help I want to delete a chat on grindr as I have been talking to a guy I'm my friend group he has sent me loads of pics but I haven't sent him any that could identify me. I am meeting him tomorrow as a friend and don't like him romantically (arranged outwith grindr) but I don't want him to see its been messaging him when we come up as close by. He also sometimes looks at my grindr if I blocked him and then unblocked him would that clear messages between both of us and I can edit my profile back to me ? I don't want to block him entirely because he knows I use grindr and will wonder why I don't come up when I'm with him many thanks