Hello! This is just for future reference.
Marriott chat is available from 7AM-11PM Monday-Friday and 9AM-8PM Saturday and Sunday, central time. There are different ways to activate a chat. For example, if you have been on a screen with inactivity, looking at packages, putting too large of a number in the occupancy that a room allows, or randomly when looking at a list of available hotels, or going to the contact us page. The invites are random and send out about 5 per chat agent.