# How to change "ab" to "cd", while "a" won't change to "c" with any letters but "b" behind it in OpenType Designer? **URL:** \ **Category:** FontCreator - Support\ **Created:** [August 8, 2019, 1:19am UTC](https://forum.high-logic.com/t/how-to-change-ab-to-cd-while-a-wont-change-to-c-with-any-letters-but-b-behind-it-in-opentype-designer/6577 "2019-08-08T01:19:54Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![Leon\_Gauthier](https://forum.high-logic.com/user_avatar/forum.high-logic.com/leon_gauthier/32/9231_2.png) [@Leon\_Gauthier](https://forum.high-logic.com/u/Leon_Gauthier)\ **Post date:** [August 10, 2019, 3:57am UTC](https://forum.high-logic.com/t/how-to-change-ab-to-cd-while-a-wont-change-to-c-with-any-letters-but-b-behind-it-in-opentype-designer/6577/2 "2019-08-10T03:57:21Z")
Just for jollies, I created a composite glyph in the private use area @ $FB07 with a name of “abform”. This glyph was a composite made of the characters “c” and “d”. In the OpenType Designer, I added a Standard Ligature 1 feature (liga) and then I added a lookup table Ligature 1 and then I added the lookup into the table. In adding elements to the lookup table, I was not able to enter “ab” in the left-hand column so that I could point it to the “cd” ligature. However, after setting up the a → cd lookup, the script editor enabled me to add the b resulting in “ab → cd”. You can see in the screen shot that where ever “ab” is encountered in the input stream, those two characters are replaced with “cd”. ![liga1sm.png](https://forum.high-logic.com/uploads/default/original/2X/2/2effb2cc189cafb4c9729dc24377982d8eb20cae.png) Good Luck The following may make this all a little clearer: [Tutorial](https://forum.high-logic.com/t/adding-opentype-features-in-fontcreator/4744/1) --- _[View the full topic](https://forum.high-logic.com/t/how-to-change-ab-to-cd-while-a-wont-change-to-c-with-any-letters-but-b-behind-it-in-opentype-designer/6577)._