text: Tell them you want better commitment from them...DON'T threaten them with the "I have replacements" line.  It may be that they are being lazy because they are unhappy about something and you don't know about it because you haven't asked.  Next, consider which musicians are better for the band...the ones you currently have or the next in line.  If the ones that you have lined up are better, and you get along with them (a slightly better player is NOT worth a band chemistry problem) then fire the lazy guys and get the better guys.\n\nBeen here, done this a few times...the best approach is to make sure everything is cool and everyone is on the same page...if you threaten them, the new guys are going to be afraid of you doing the same to them some day down the line.