How can i change the revision number for catalyst 4500 switch. can you tell me the commands that i needed.
If your both switches are belongs to one VTP domain, then you just have to configure your 4500 switch as VTP Server and domain name and connect to the network. Switch automatically loads Vlan & VTP parameters from 2950 switch (revision no also sets to 23).
Hope this helps
Assuming you mean the VTP revision number it depends on what you want to achieve.
1) If you want to set the revision number back to 0 and the switch is in vtp server mode then change the vtp mode on your switch to vtp transparent and then back to vtp server.
2) If the switch is in VTP client mode and you want to update it you need to either
a) change the mode to vtp server and then make an update to the vlan database
b) more likely you need to update the switch acting as a vtp server and this will then automatically update your VTP client switch.
To update the revision number on a VTP server switch you need to make a modification to the vlan database ie. create a new vlan, modify the details of an existing vlan or delete a vlan.