Editing a routemap line for BGP

[nzmatto]

Hi team, 

I have a client who is expanding their current /16 network to a /15 and now I need to edit the existing routemap. What I need to know is the correct command syntax to remove only one individual line from the routemap, and when will the change take effect in BGP. 

The existing line "set routemap from_vendor id 10 match network 10.100.0.0/16 all" needs to be changed to match network 10.100.0.0/15. My assumption is I should be able to just enter the command "set routemap from_vendor id 10 match network 10.100.0.0/15 all" to add the new line, but how to I remove the old /16 without having to remove the whole routemap. 

Once I have made the change when will BGP re-read the routemap to start accepting routes in the /15 range? I am hoping to do this without a disruption to service if possible.

Thanks for your help

Matt

[nzmatto]

I have found the first part

set routemap from_vendor id 10 match network 10.100.0.0/15 all

set routemap from_vendor id 10 match network 10.100.0.0/16 off

That will add the /15 before removing the /16 however I don't know when it will actually become active. When is the routemap actually checked?