How to replace different numbers in the memory. Conair 13 memory speakerphone.

1) Press "STORE"

2) Dial the number you wish to save in a memory location.

3) Press either the "Priority Memory" keys (M1, M2, M3) or a keypad
number (0 through 9) to save the dialed number in that location.

To dial a stored number, if it's a "Priority Memory" number, just
press the key (M1, M2, or M3). If it's a number stored in 0 through
9, press "MEMORY", then the desired number key.

Here's a link to a manual for a ConairPhone memory phone:

http://www.conairphone.com/IBs/feature_telephone/sw6404.pdf